Astronomers have been treated to a stunning fireworks display from around a young star called Fomalhaut. The events, detected in 2004 and 2023, represent the first collisions between large objects seen in a planetary system beyond our own. Observing collisions occurring in a young star system like that of Fomalhaut could provide astronomers with a window to the conditions under which our own planet and its siblings formed around the infant sun around 4.6 billion years ago.

Fomalhaut is located only around 25 light-years away and is just 440 million years old. If this seems far from "young," remember our planet is 4.6 billion years old, and is considered middle-aged. Young star systems like Fomalhaut are estimated to be a hub of such violent collisions as space rocks, asteroids, and larger planetesimals, objects smaller than dwarf planets, slam into each other. Often, planetesimals rebound away from each other, but sometimes they stick to one another and turn dust and ice into planets and moons. The largest collisions are rare, occurring maybe once every 100,000 years over the hundreds of millions of years it takes to form a planetary system like the solar system.

"We just witnessed the collision of two planetesimals and the dust cloud that gets spewed out of that violent event, which begins reflecting light from the host star," team leader Paul Kalas, of the University of California, Berkeley, said in a statement. It's like looking back in time in a sense, to that violent period of our solar system when it was less than a billion years old."

Kalas added that the team did not directly see the two objects that crashed into each other, instead spotting the aftermath of this enormous impact.

He and his colleagues first began investigating the young star Fomalhaut back in 1993, hunting for the debris leftover from planet birth, eventually finding a disk of this material around the star with the Hubble Space Telescope. Then, in 2008, Kalas found a bright spot in that so-called protoplanetary disk that was initially thought to be a planet. This new research suggests that this planet, Fomalhaut b, is actually a dust cloud that was stirred up by the collision between planetesimals in the protoplanetary disk.

"This is a new phenomenon, a point source that appears in a planetary system and then over 10 years or more slowly disappears," Kalas said. "It's masquerading as a planet because planets also look like tiny dots orbiting nearby stars."

The brightness of the events observed in 2004 and 2023 revealed that the bodies involved were around 37 miles wide (60 kilometers) or more, meaning they are each at least four times as large as the Chicxulub impactor, the asteroid that struck Earth 66 million years ago, wiping out the dinosaurs along with 75% of all species of animals and plants.

"The Fomalhaut system is a natural laboratory to probe how planetesimals behave when undergoing collisions, which in turn tells us about what they are made of and how they formed," team member Mark Wyatt, of the University of Cambridge in the United Kingdom, said. "The exciting aspect of this observation is that it allows us to estimate both the size of the colliding bodies and how many of them there are in the disk, information which is almost impossible to get by any other means." Indeed, the team estimates that there are around 300 million planetesimals in the region around Fomalhaut of sizes similar to those involved in these two crashes. The fact that carbon monoxide gas has previously been detected in this system indicates these objects are rich in volatiles, substances such as hydrogen, nitrogen, oxygen and methane that easily turn gaseous at low temperatures.

That makes these icy bodies in Fomalhaut similar to the frigid comets of the solar system, which are also packed with volatiles. In a further comparison with the solar system, Kalas suggested that the 2004 and 2023 dust clouds seen by the team are akin to the dust cloud created in 2022 when NASA struck the moonlet Dimorphos with the DART (Double Asteroid Redirection Test) to test if this could shift its parent asteroid Didemos.

Kalas and colleagues will continue to investigate Fomalhaut with Hubble, also adding the powerful infrared vision of the James Webb Space Telescope to their investigation. This should allow them to track how the cloud seen in 2023 evolves. It is already around 30% brighter than the 2003 cloud, and observations conducted in August 2025 confirmed that it is indeed still visible.

As this investigation continues, Kalas warns astronomers not to fall into the trap of mistaking dust clouds for newly formed planets around infant stars.

"These collisions that produce dust clouds happen in every planetary system," Kalas said. "Once we start probing stars with sensitive future telescopes such as the Habitable Worlds Observatory, which aims to directly image an Earth-like exoplanet, we have to be cautious because these faint points of light orbiting a star may not be planets."

The team's research was published on Thursday (Dec. 18) in the journal Science.

Since astronomers discovered the first world outside the solar system in the mid-1990s, these extra-solar planets or "exoplanets" have astounded us with their strange characteristics.

A new discovery, made using the James Webb Space Telescope (JWST), may just be the weirdest exoplanet yet, possessing an atmosphere unlike any we've ever seen on an exoplanet. Currently, the team behind this discovery can't explain how such a planet came to be.

The planet, designated PSR J2322-2650b, has a mass around that of Jupiter and orbits a dead star called a pulsar that blasts out twin jets of radiation that sweep across the universe like a cosmic lighthouse. Technically, the system is classified as a "black window pulsar," a binary star normally containing both a pulsar and stellar body, which the pulsar erodes and devours with its jets of radiation.

That isn't in itself so strange. The first planets beyond the solar system ever confirmed, Poltergeist (PSR B1257+12 B) and Phobetor (PSR B1257+12 C), spotted in 1992, also orbit pulsars, a young, rapidly spinning form of neutron star.

However, what sets PSR J2322-2650b apart are the facts that it has an ellipsoid shape, like a planetary lemon or football, and that it has an atmosphere like none scientists have ever seen before.

"This was an absolute surprise," team member Peter Gao of the Carnegie Earth and Planets Laboratory said in a statement. "I remember after we got the data down, our collective reaction was 'What the heck is this?' It's extremely different from what we expected."

The atmosphere of PSR J2322-2650b is dominated by helium and carbon, and likely has clouds of carbon soot that condense to create diamonds that rain down onto the planet.

At just around 1 million miles (1.6 million km) from its pulsar parent star (the Earth is around 100 times as distant from the sun), PSR J2322-2650b completes an orbit once every 8 hours or so. Its lemon-like shape emerges from tidal forces generated within the planet by the powerful gravity of the dead star it clings to.

"A new type of planet atmosphere that nobody has ever seen before"

Like all neutron stars, pulsars are born when massive stars at least 10 times the size of the sun exhaust the fuel for nuclear fusion. This results in the star's outer layers, and most of its mass, being blown away in a supernova explosion.

Left behind is a core with between 1 and 2 times the mass of the sun that crushes down to a width of around 12 miles (20 kilometers), and because it retains angular momentum, it can spin as fast as 700 times per second!

The parent star of PSR J2322-2650b is just such a so-called millisecond pulsar, but while it blasts out intense gamma-ray radiation, it doesn't emit very much infrared light. Because the JWST has been designed to see the cosmos in infrared, that means this powerful dead star doesn't block the $10 billion space telescope's view of PSR J2322-2650b.

This allowed the team to investigate the atmosphere of PSR J2322-2650b in detail and uncover its unique composition.

"This is a new type of planet atmosphere that nobody has ever seen before," team leader Michael Zhang of the University of Chicago said. "Instead of finding the normal molecules we expect to see on an exoplanet — like water, methane, and carbon dioxide — we saw molecular carbon, specifically carbon-3 and carbon-2."

PSR J2322-2650b is tidally locked to its star, which means one side permanently faces the neutron star, the planet's dayside, while the other faces out into space in perpetuity, its nightside.

The dayside of PSR J2322-2650b has a maximum temperature of 3,700 degrees Fahrenheit (2,040 degrees Celsius), while the nightside has a minimum temperature of 1,200 degrees Fahrenheit (650 degrees Celsius).

At these temperatures, molecular carbon should bind with other types of atoms, only becoming dominant if there is almost no oxygen or nitrogen in the planet's atmosphere. Of the 150 or so exoplanet atmospheres studied to date, no others have possessed detectable molecular carbon.

"Did this thing form like a normal planet? No, because the composition is entirely different," Zhang said. "Did it form by stripping the outside of a star, like 'normal' black widow systems are formed?

"Probably not, because nuclear physics does not make pure carbon. It's very hard to imagine how you get this extremely carbon-enriched composition. It seems to rule out every known formation mechanism."

There is one possible route of the creation of this planet, hinging on a unique phenomenon occurring in the bizarre atmosphere of PSR J2322-2650b.

"As the companion cools down, the mixture of carbon and oxygen in the interior starts to crystallize. Pure carbon crystals float to the top and get mixed into the helium, and that's what we see," team member and Stanford University researcher Roger Romani said. "But then something has to happen to keep the oxygen and nitrogen away. And that's where the mystery comes in.

“But it's nice not to know everything. I'm looking forward to learning more about the weirdness of this atmosphere. It's great to have a puzzle to go after."

This exoplanet is six times closer to its parent stars than any previously directly imaged binary system exoplanet, yet despite this relative proximity, it still has a year that lasts 300 times as long as an Earth year.

The discovery of this planet, designated HD 143811 AB b (referring to the fact that it orbits the stars HD 143811 A and HD 143811 B in the system HD 143811 AB), and located 446 light-years away from Earth, is an exciting find for scientists. That is because planets are very rarely detected around binary stars, meaning HD 143811 AB b offers a rare chance to study how stars and planets orbit together, while also investigating planet formation mechanisms.

"Of the 6,000 exoplanets that we know of, only a very small fraction of them orbit binaries," team member and exoplanet imaging expert Jason Wang of Northwestern University said in a statement. "Of those, we only have a direct image of a handful of them, meaning we can have an image of the binary and the planet itself. Imaging both the planet and the binary is interesting because it’s the only type of planetary system where we can trace both the orbit of the binary star and the planet in the sky at the same time.

"We're excited to keep watching it in the future as they move, so we can see how the three bodies move across the sky."

A new discovery from decade-old data

This exoplanet may be new to astronomers, but it isn't actually a new observation. Wang and colleagues discovered HD 143811 AB b in archival data collected almost 10 years ago by the Gemini South telescope and its Gemini Planet Imager (GPI) instrument. GPI captured images of exoplanets by blocking out the overwhelming glare of their parent stars using a coronagraph, an instrument that acts almost like the artificial equivalent of an eclipse. The instrument then used adaptive optics to sharpen the images of these faint planets around their bright stars.

GPI operated from 2014 to 2022, when it was removed from Gemini South and transferred to the University of Notre Dame in Indiana to undergo a major upgrade of the whole system called GPI 2.0. Next year, once upgrades are completed, GPI 2.0 will be moved to the Gemini North telescope atop Mauna Kea, Hawaii.

This discovery came about when Wang and colleagues decided to revisit the GPI data ahead of its new life as GPI 2.0. "I didn’t think we’d find any new planets," Wang said. "But I thought we should do our due diligence and check carefully anyway."

"During the instrument's lifetime, we observed more than 500 stars and found only one new planet," Wang said. "It would have been nice to have seen more, but it did tell us something about just how rare exoplanets are."

Team member Nathalie Jones of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) assessed GPI data gathered over three years between 2016 and 2019, cross-referencing it with data collected by the W.M. Keck Observatory. This led to a tantalizing discovery, a faint object following the motion of a star.

"Stars don't stand still in a galaxy; they move around," Wang explained. "We look for objects and then revisit them later to see if they have moved elsewhere. If a planet is bound to a star, then it will move with the star. Sometimes, when we revisit a 'planet,' we find it's not moving with its star, then we know it was just a photobombing star passing through. If they are both moving together, then that's a sign that it’s an orbiting planet."

Astronomers can determine the difference between light coming directly from a star and light being reflected by a planet, meaning they can also look at data and compare it to what it would look like if a mystery object is indeed a planet. These tests allowed Jones to determine that HD 143811 AB b is indeed a planet that was first captured by GPI in 2016 but was subsequently missed by astronomers. This conclusion was also arrived at by an independent team of astronomers from the University of Exeter in the UK.

Astronomers were also able to learn a lot more about HD 143811 AB b, discovering that this planet is a whopper, at around six times the size of Jupiter. The planet was also determined to be around 13 million years old, which may sound ancient until you consider the Earth is 4.6 billion years old.

"That sounds like a long time ago, but it's 50 million years after dinosaurs went extinct," Wang said. "That's relatively young in universe speak, so it still retains some of the heat from when it formed."

It isn't just the planet that is relatively close to its binary stellar parents; these stars are also quite close together, taking just 18 Earth days to orbit each other. Yet, despite its proximity to the stars compared to other planets found in binary systems, HD 143811 AB b still takes 300 Earth-years to complete just one orbit.

What the team doesn't yet understand is quite how this planet formed around its binary stars.

"Exactly how it works is still uncertain," Wang said. "Because we have only detected a few dozen planets like this, we don’t have enough data yet to put the picture together."

Answering this question could require the team to further study HD 143811 AB.

"I'm asking for more telescope time, so we can continue looking at this planet," Jones said. "We want to track the planet and monitor its orbit, as well as the orbit of the binary stars, so we can learn more about the interactions between binary stars and planets."

In the meantime, Jones intends to continue hunting through archival data to discover more planets. "There are a couple of suspicious objects, but what they are, exactly, remains to be seen," Jones concluded.

The team's research was published on Thursday (Dec. 11) in The Astrophysical Journal Letters.

The findings challenge the prevailing wisdom that relatively small planets orbiting extremely close to their stars cannot sustain atmospheres.

The ultra-hot super-Earth, TOI-561 b, is the innermost of at least three planets circling a 10-billion-year-old star located about 280 light-years from Earth. The planet orbits at just one-fortieth the distance between Mercury and the sun, completing a full orbit in under 11 hours.

That extreme proximity places it in a class of ultra-short-period super-Earths that are heated to temperatures high enough to melt rock. Under such conditions, scientists generally expect planets to lose any atmosphere due to intense stellar radiation, leaving behind bare, airless rock. But observations from NASA's TESS space telescope have shown TOI-561 b has an unusually low density for a purely rocky world, suggesting that another explanation may be needed.

"It must have formed in a very different chemical environment from planets in our own solar system," Johanna Teske, a staff scientist at the Carnegie Earth and Planets Lab in Washington D.C. who led the new paper, said in a statement.

To test whether the planet has an atmosphere, the team used the JWST's NIRSpec instrument to measure the temperature of TOI-561 b's dayside. In May 2024, JWST observed the planet–star system continuously for more than 37 hours, capturing four full orbits. Scientists focused on moments when the planet passed behind its star, events known as "secondary eclipses" when the planet's own light briefly disappeared. By measuring the tiny drop in the system's total brightness during each eclipse, the team could isolate the planet's infrared glow and directly determine its dayside temperature.

If TOI-561 b had no atmosphere, its dayside should reach roughly 4,900 degrees Fahrenheit (2,700 degrees Celsius). Instead, the JWST measured a temperature much cooler, around 3,100 degrees Fahrenheit (1,700 degrees Celsius). To understand why, the researchers tested a range of possible surfaces and atmospheric types to see which could reproduce the signal observed by JWST.

"We really need a thick volatile-rich atmosphere to explain all the observations," study co-author Anjali Piette of the University of Birmingham said in the statement. "Strong winds would cool the dayside by transporting heat over to the nightside."

The team suggests the planet may maintain a balance between its molten surface and its atmosphere, allowing gases to cycle between them and potentially replenishing its atmosphere.

"While gases are coming out of the planet to feed the atmosphere, the magma ocean is sucking them back into the interior," study co-author Tim Lichtenberg of the University of Groningen in the Netherlands said in the statement. "It's really like a wet lava ball."

The results open the door to probe the interiors and geological activity of such extremely hot rocky planets by studying their atmospheres, the researchers note.

The findings were published on Dec. 11 in the The Astrophysical Journal Letters.

The extrasolar planet, or exoplanet, in question is WASP-121b, also known as "Tylos," located around 858 light-years away. WASP-121b is an example of an "ultrahot Jupiter," a massive gas giant planet found so close to its parent star that it can complete an orbit in a matter of hours. As WASP-121b whips around its star once every 30 hours, intense radiation from its stellar parent heats its atmosphere to around 4,200 degrees Fahrenheit (2,300 degrees Celsius).

When a planet undergoes this type of heating, it causes gases of lighter elements like hydrogen and helium to flow into space, a slow atmospheric escape lasting millions of years that alters the planet's size, composition, and how it will evolve. Previously, scientists had caught glimpses of atmospheric escape as exoplanets passed in front of their parent stars, an event called a "transit." But this left a gap in our understanding of this process because scientists couldn't be sure if planetary atmospheres continued to leak outside of those few hours when the planets were observed during a transit.

These new observations, made using the JWST's Near-Infrared Spectrograph (NIRSpec) over around 37 consecutive hours, therefore represent the first most comprehensive continuous observation ever made of the presence of helium on a planet and how it leaks during a complete orbit.

"We were incredibly surprised to see how long the helium escape lasted," team leader Romain Allart, of the University of Montreal, said in a statement. "This discovery reveals the complexity of the physical processes that sculpt exoplanetary atmospheres and their interaction with their stellar environment. We are only beginning to discover the true complexity of these worlds.

A tale of two tails

Helium is one of the most important tracers of atmospheric escape from exoplanets, and the incredible sensitivity of the JWST allows the element to be observed at vast distances. Tracking the light absorbed by helium atoms, the researchers found that the envelope of gas around WASP-121b stretches out far beyond this hot Jupiter. The helium signal lasted for over half the orbit of the planet, making this the longest continuous detection of atmospheric escape yet.

The most remarkable thing about this investigation is the fact that the helium leaking from WASP-121b forms two distinct tails, one of which is pushed back behind the exoplanet by radiation and stellar winds from its parent star. The other tail leads the planet in its orbit, likely pulled forward toward the star by its gravity.

Combined, the helium tails are 100 times as long as WASP-121b is wide, and three times the distance between the hot Jupiter and its star. And the dual tails are something that scientists can't explain with current models.

"Very often, new observations reveal the limitations of our numerical models and push us to explore new physical mechanisms to further our understanding of these distant worlds," team member Vincent Bourrier, of the Department of Astronomy at the Faculty of Science of the University of Geneva, said.

The team's research was published on Monday (Dec. 8) in the journal Nature Communications.

However, astronomers in Hawaii just spotted a pair of exciting discoveries — a huge exoplanet and a brown dwarf — using Japan’s Subaru Telescope, which sits atop Mauna Kea, a dormant volcano on the Big Island of Hawaii.

These new celestial discoveries represent the first findings from OASIS (Observing Accelerators with SCExAO Imaging Survey), a program that relies on the Subaru Telescope, as well as data from other sources.

"The program uses measurements from two European Space Agency missions — Hipparcos and Gaia — to identify stars being tugged by the gravity of unseen companions," a spokesperson from the National Astronomical Observatory of Japan (NAOJ) wrote in a statement.

The exoplanet that the astronomers found is called HIP 54515 b. It's 271 light-years away from Earth and orbits a star in the Leo constellation. NAOJ says the planet is almost 18 times the mass of Jupiter and that it orbits its star from a vantage point that’s roughly the same as Neptune's distance from the sun.

The brown dwarf, called HIP 71618 B, is 169 light-years away in the Bootes constellation. The term "brown dwarf" refers to a curious celestial object that has a mass somewhere between a planet and a star. Scientists often call brown dwarfs "failed stars," because these objects form in a similar way to stars but never accumulate quite enough mass to make the cut.

The discovery of the brown dwarf is especially exciting, because it has the right properties to test out NASA's new Nancy Grace Roman Space Telescope, which will launch in 2026 or 2027.

To test the Roman Space Telescope, NASA needs an object with pretty tight specifications. NAOJ says this brown dwarf checks all the boxes. "Roman will carry out a technology demonstration to test coronagraph systems that future telescopes will need to photograph Earth-like planets around other stars — planets that are ten billion times fainter than their host stars," NAOJ wrote.

So, with this new discovery, NAOJ says, Roman will have the right candidate for a technology demonstration.

TRAPPIST-1e is one of seven Earth-size exoplanets tightly packed around a cool red dwarf star smaller and dimmer than our sun that's about 40 light-years away. It orbits in the system's "habitable zone," where temperatures could allow liquid water to exist — but that's only if the planet has an atmosphere. Early James Webb Space Telescope (JWST) observations even hinted at a possible atmosphere, revealing faint signatures of methane, which, on Earth, results from living organisms and is tied to complex chemistry on Saturn's haze-shrouded moon Titan.

But those first glimmers, scientists now say, were likely misleading.

"Based on our most recent work, we suggest that the previously reported tentative hint of an atmosphere is more likely to be 'noise' from the host star," Sukrit Ranjan, an assistant professor at the University of Arizona Lunar and Planetary Laboratory, said in a statement. "However, this does not mean that TRAPPIST-1e does not have an atmosphere — we just need more data."

The new paper uses detailed computer simulations to test whether TRAPPIST-1e could realistically maintain a methane-rich, Titan-like atmosphere. The results suggest methane on a world orbiting a small, active red dwarf star like TRAPPIST-1 would be destroyed much faster than on Titan — too quickly for any plausible geological process to replenish it.

The latest findings build on two papers published in September that analyzed the JWST's 2023 observations of TRAPPIST-1e. During four separate transits when the planet crossed the face of its star, the JWST's Near-Infrared Spectrograph (NIRSpec) instrument recorded subtle changes in starlight that could, in principle, reveal atmospheric chemicals. The data were consistent with an atmosphere dominated by nitrogen and methane and lacking carbon dioxide, effectively ruling out a Venus- or Mars-like atmosphere.

But the signals varied significantly from transit to transit, hinting that the measurements were being contaminated by the star itself. TRAPPIST-1 is smaller, cooler and far dimmer than our sun, cool enough that gas molecules, including methane, can form in the star's own atmosphere.

"We reported hints of methane, but the question is, 'is the methane attributable to molecules in the atmosphere of the planet or in the host star?'" Ranjan said in the statement.

In the paper, Ranjan and his team modeled how long methane could realistically survive in TRAPPIST-1e's environment. They found that while Titan's methane can persist for 10 million to 100 million years, methane on TRAPPIST-1e would last only about 200,000 years. The planet receives far more ultraviolet radiation than Titan, causing methane to be broken apart thousands of times faster, the study notes.

That makes it extraordinarily unlikely that scientists would catch the planet during a methane-rich phase unless methane were being replenished at extreme, continuous rates, the researchers say. Maintaining Titan-like levels would require TRAPPIST-1e to outproduce Titan in methane generation, an implausible scenario that would demand nonstop global volcanism, catastrophic methane release from an icy interior, or constant planetary resurfacing. Even under generous assumptions, these processes cannot fully account for the required methane supply, the study notes.

As a result, the team concludes that more rigorous analysis and additional observations are needed to determine whether TRAPPIST-1e has any atmosphere at all, and whether the JWST's tentative methane hints originate from the planet or are simply artifacts of the star.

"The basic thesis for TRAPPIST-1e is this: If it has an atmosphere, it's habitable," Ranjan said in the statement. "But right now, the first-order question must be, 'Does an atmosphere even exist?'"

Despite the challenges, TRAPPIST-1e remains one of the most promising potentially habitable worlds beyond our solar system. However, JWST, designed before the first exoplanet was discovered, is operating at the limits of its sensitivity when probing the atmospheres of Earth-sized planets.

Future instruments may help disentangle the confusing signals. NASA's upcoming Pandora mission, scheduled for launch in 2026, will observe stars and planets simultaneously to better separate stellar and atmospheric features.

The researchers are also planning a rare dual-transit observation in which TRAPPIST-1e and the innermost planet TRAPPIST-1b cross the star together. TRAPPIST-1b is known to lack an atmosphere, so comparing its "clean" signal to TRAPPIST-1e's could reveal which features belong to the star and which — if any — arise from TRAPPIST-1e's atmosphere, scientists say.

"These observations will allow us to separate what the star is doing from what is going on in the planet's atmosphere — should it have one," said Ranjan.

The paper about these results was published on Nov. 3 in The Astrophysical Journal Letters.

TRAPPIST-1 is an ultracool red dwarf, located about 40 light-years away in the constellation Aquarius. It hosts seven Earth-size planets, three of which orbit in the so-called "habitable zone" where liquid water might exist. However, the small star is notoriously active, erupting with energy bursts roughly six times per day, which can threaten planetary atmospheres within the system and obstruct observations, according to a statement from the University of Colorado Boulder.

Using data from the James Webb Space Telescope (JWST), researchers tracked six flares observed in 2022 and 2023. These flares appear as a big flash detectable by the JWST's infrared sensors, revealing how much heat the star releases during an outburst. By combining these observations with computer simulations, the team reconstructed the physical processes driving each flare, allowing them to estimate the properties of the electron beams that trigger these stellar tantrums.

"If we can simulate these events using a computer model, we can reverse engineer how a flare might influence the radiation environment around each of these planets," Ward Howard, lead author of the study, said in the statement. This, in turn, can help determine which worlds might retain atmospheres capable of supporting life.

Surprisingly, the electron beams powering these flares appear about ten times weaker than those seen in similar stars. That doesn't mean they're harmless — each flare emits radiation across the spectrum, from visible light to ultraviolet radiation and powerful X-rays, all of which can erode or alter planetary atmospheres over time.

As a result, the researchers suggested that the innermost TRAPPIST-1 planets may have lost their atmospheres, potentially leaving them as bare rocks, while one planet in the habitable zone, TRAPPIST-1e, could still retain a thin, Earth-like atmosphere — a tentative sign that it might support conditions favorable to life.

By decoding TRAPPIST-1's flare behavior, scientists can refine predictions about which planetary atmospheres might survive its constant outbursts. Rather than mere observational nuisances or purely destructive forces, these eruptions can be read as messages from the star, offering key insights into the potential habitability of its planets and informing the broader search for life beyond Earth.

Their findings were published Nov. 20 in the Astrophysical Journal Letters.

The final integration of the telescope's major observatory components took place on Nov. 25 inside NASA's Goddard Space Flight Center in Greenbelt, Maryland, where engineers brought together the spacecraft and telescope assemblies in the facility's largest clean room, according to a statement from NASA.

"Completing the Roman observatory brings us to a defining moment for the agency," Amit Kshatriya, NASA Associate Administrator, said in the statement. "Transformative science depends on disciplined engineering, and this team has delivered — piece by piece, test by test — an observatory that will expand our understanding of the universe. As Roman moves into its final stage of testing following integration, we are focused on executing with precision and preparing for a successful launch on behalf of the global scientific community."

Roman is designed to survey the universe with unprecedented efficiency using two primary instruments: the Wide Field Instrument (WFI) — a powerful infrared camera with a field of view larger than that of the Hubble Space Telescope at comparable resolution — and a next-generation Coronagraph Instrument that will image exoplanets by blocking light from distant stars, making it easier to see the planets in orbit around them. Together, these instruments will map cosmic structures on grand scales, probe dark energy, measure the distribution of dark matter, detect isolated black holes through microlensing and identify potentially tens of thousands of distant exoplanets, according to the statement.

With physical construction complete, Roman now shifts into a lengthy campaign of environmental and performance testing under simulated space conditions designed to verify that the spacecraft can survive the stresses of launch and operate as intended once in space. After that, the telescope will be shipped to NASA's Kennedy Space Center in Florida this summer for final processing and integration with its launch vehicle. While the mission is slated to launch by May 2027, it could be ready as early as fall 2026, NASA officials said.

If all goes as planned, Roman will launch aboard a SpaceX Falcon Heavy rocket to a gravitationally stable orbit around the sun nearly a million miles from Earth. During its planned five-year primary mission, Roman is expected to observe billions of galaxies and hundreds of millions of stars, providing new clues about the accelerating expansion of the universe. Mission scientists also expect the telescope to detect more than 100,000 exoplanets by monitoring subtle gravitational lensing events, whereby a larger foreground object magnifies the light from a more distant source that cannot otherwise be observed directly.

"With Roman's construction complete, we are poised at the brink of unfathomable scientific discovery," Julie McEnery, Roman's senior project scientist at NASA Goddard, said in the statement. "We stand to learn a tremendous amount of new information about the universe very rapidly after Roman launches."

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Using observations from the European Southern Observatory's (ESO) Very Large Telescope, astronomers documented 51 budding exoplanetary systems after studying 161 nearby stars, offering an unprecedented glimpse at debris disks around stars beyond our solar system. These debris disks are formed by collisions between asteroids or comets that generate large amounts of dust and resemble our own solar system where asteroids collect in the inner belt and comets populate the distant Kuiper Belt, according to a statement.

"This data set is an astronomical treasure," Gaël Chauvin, co-author of the study and SPHERE project scientist, said in the statement. "It provides exceptional insights into the properties of debris disks, and allows for deductions of smaller bodies like asteroids and comets in these systems, which are impossible to observe directly."

Scientists study debris disks because they offer a snapshot of what young solar systems look like after planets begin to form. Young stars form within collapsing clouds of gas and dust, which flatten into broad protoplanetary disks where material gradually clumps into larger bodies. As these systems mature, collisions between leftover asteroids and comets produce fine dust creating the debris disks we see today. By examining how this dust reflects starlight, astronomers can piece together how planets grow and how systems like our own take shape over time.

However, debris disks fade as collisions become less frequent and dust is gradually removed — either because it's blown out by stellar radiation, swept up by planets or remaining planetesimals or has fallen into the central star. Our solar system is an example of the end state of this process, with just the asteroid belt, the Kuiper Belt and faint zodiacal dust remaining.

Using advanced instruments like SPHERE allows astronomers to study the dust in younger systems — roughly the first 50 million years — that can still be detected. Most importantly, SPHERE blocks starlight using a coronagraph, a small disk that physically masks the star to reveal faint surrounding objects. The telescope's adaptive optics system corrects for atmospheric distortions in real time, and optional polarization filters enhance sensitivity to light reflected by dust, making debris disks easier to detect.

The new survey reveals remarkable variety, from narrow rings to wide diffuse belts, lopsided disks and disks viewed both edge-on and face-on. In fact, four of the disks were imaged in this detail for the first time, the researchers said.

Striking views of HD 197481 and HD 39060 capture sharp streams of material darting out from either side of its central star (representing an edge-on view), while incredible views of systems like HD 109573 and 181327 capture a nearly perfect circular debris ring (representing a face-on view).

In many systems, dust congregates in sharply defined rings, hinting at unseen planets shaping the debris, much like Neptune molds the Kuiper Belt in our solar system. On the other hand, the dust distribution in younger systems like HD 145560 and HD 156623 is more chaotic and billowy, where less defined structures suggest material hasn't yet been fully sculpted by planets or cleared by collisions.

Comparing the different structures within the disks revealed clear trends, like more massive stars tend to host more massive disks, and disks with material concentrated farther from the star also generally contain more mass, according to the statement.

"All of these belt structures appear to be associated with the presence of planets, specifically of giant planets, clearing their neighborhoods of smaller bodies," researchers said in the statement. "In some of the SPHERE images, features like sharp inner edges or disk asymmetries give tantalizing hints of as-yet unobserved planets."

While some giant exoplanets have already been detected in these systems, the SPHERE survey offers a guide post for new targets to be studied in greater detail by instruments like the James Webb Space Telescope and ESO's Extremely Large Telescope, which could reveal the exoplanets responsible for sculpting these spectacular disks.

Their findings were published Dec. 3 in the journal Astronomy and Astrophysics.

The findings may help to explain why Earth became geologically vibrant while Venus remained stagnant and scorching, with possible implications for our understanding of what makes a planet habitable.

When researchers used advanced geodynamic simulations to map diverse planetary tectonic regimes — distinct patterns that describe how a planet's outer shell deforms and releases heat under different conditions — they discovered a missing link they've dubbed the "episodic-squishy lid."

This striking new framework offers a fresh perspective on how planets shift between active and inactive states, thus reshaping scientific assumptions about planetary evolution and habitability, the team said in a statement explaining the study.

Tectonic regimes influence a planet's geological activity, internal evolution, magnetic field, atmosphere and even its potential to support life. The episodic-squishy lid builds on the traditional divide between plate tectonics or mobile lid regimes (like modern Earth) and stagnant-lid behavior (like Mars). It describes a state in which a planet's lithosphere cycles between relatively quiet periods and sudden bursts of tectonic motion. Unlike a classic stagnant lid, this regime permits intermittent weakening driven by intrusive magmatism and regional delamination, temporarily softening the crust before it stiffens again.

This on-again, off-again behavior could be a missing link in Earth's early evolution, the researchers said. The models suggest that Earth may have passed through a squishy-lid phase that gradually primed its lithosphere for full plate tectonics as the planet cooled.

The findings also help to clarify the "memory effect" — the idea that a planet's tectonic behavior is shaped by its past — by showing that as a planet's lithosphere weakens over time, as Earth's did, the transitions between tectonic states become far more predictable.

By mapping all six tectonic regimes under different physical conditions for the first time, the team constructed a comprehensive diagram revealing likely transition pathways as a planet cools.

"Geological records suggest that tectonic activity on early Earth aligns with the characteristics of our newly identified regime," study co-author Guochun Zhao, a geologist at the Chinese Academy of Sciences, said in the statement. "As Earth gradually cooled, its lithosphere became more prone to fracturing under specific physical mechanisms, eventually leading to today's plate tectonics. This provides a key piece of the puzzle in explaining how Earth became a habitable planet."

The episodic-squishy lid may also shed light on Venus's long-standing mysteries. Although Venus is roughly the same size as Earth, it lacks clear evidence of plate tectonics, instead displaying volcanically reshaped terrain and distinctive features called coronae. The new simulations reproduce Venus-like patterns by placing the planet in an episodic or plutonic squishy-lid regime, where magmatism and mantle plumes periodically weaken the surface without generating true plates.

"Our models intimately link mantle convection with magmatic activity," study co-author Maxim Ballmer, an associate professor of geodynamics at University College London, said in the statement. "This allows us to view the long geological history of Earth and the current state of Venus within a unified theoretical framework, and it provides a crucial theoretical basis for the search for potentially habitable Earth analogs and super-Earths outside our solar system."

Because tectonics govern how water and carbon dioxide circulate through a planet's interior and atmosphere, understanding how lithospheres weaken and transition between regimes could help scientists assess which distant worlds might support stable climates, or even life, and guide decisions on observational targets for future missions.

The findings were published Nov. 24 in the journal Nature Communications.

When astronomers search for planets that could host liquid water on their surface, they start by looking at a star's habitable zone. Water is a key ingredient for life, and on a planet too close to its star, water on its surface may "boil"; too far, and it could freeze. This zone marks the region in between.

But being in this sweet spot doesn't automatically mean a planet is hospitable to life. Other factors, like whether a planet is geologically active or has processes that regulate gases in its atmosphere, play a role.

The habitable zone provides a useful guide to search for signs of life on exoplanets – planets outside our solar system orbiting other stars. But what's in these planets' atmospheres holds the next clue about whether liquid water — and possibly life — exists beyond Earth.

On Earth, the greenhouse effect, caused by gases like carbon dioxide and water vapor, keeps the planet warm enough for liquid water and life as we know it. Without an atmosphere, Earth's surface temperature would average around zero degrees Fahrenheit (minus 18 degrees Celsius), far below the freezing point of water.

The boundaries of the habitable zone are defined by how much of a "greenhouse effect" is necessary to maintain the surface temperatures that allow for liquid water to persist. It's a balance between sunlight and atmospheric warming.

Many planetary scientists, including me, are seeking to understand if the processes responsible for regulating Earth's climate are operating on other habitable zone worlds. We use what we know about Earth’s geology and climate to predict how these processes might appear elsewhere, which is where my geoscience expertise comes in.

Why the habitable zone?

The habitable zone is a simple and powerful idea, and for good reason. It provides a starting point, directing astronomers to where they might expect to find planets with liquid water, without needing to know every detail about the planet's atmosphere or history.

Its definition is partially informed by what scientists know about Earth's rocky neighbors. Mars, which lies just outside the outer edge of the habitable zone, shows clear evidence of ancient rivers and lakes where liquid water once flowed.

Similarly, Venus is currently too close to the sun to be within the habitable zone. Yet, some geochemical evidence and modeling studies suggest Venus may have had water in its past, though how much and for how long remains uncertain.

These examples show that while the habitable zone is not a perfect predictor of habitability, it provides a useful starting point.

Planetary processes can inform habitability

What the habitable zone doesn't do is determine whether a planet can sustain habitable conditions over long periods of time. On Earth, a stable climate allowed life to emerge and persist. Liquid water could remain on the surface, giving slow chemical reactions enough time to build the molecules of life and let early ecosystems develop resilience to change, which reinforced habitability.

Life emerged on Earth, but continued to reshape the environments it evolved in, making them more conducive to life.

This stability likely unfolded over hundreds of millions of years, as the planets surface, oceans and atmosphere worked together as part of a slow but powerful system to regulate Earth’s temperature.

A key part of this system is how Earth recycles inorganic carbon between the atmosphere, surface and oceans over the course of millions of years. Inorganic carbon refers to carbon bound in atmospheric gases, dissolved in seawater or locked in minerals, rather than biological material. This part of the carbon cycle acts like a natural thermostat. When volcanoes release carbon dioxide into the atmosphere, the carbon dioxide molecules trap heat and warm the planet. As temperatures rise, rain and weathering draw carbon out of the air and store it in rocks and oceans.

If the planet cools, this process slows down, allowing carbon dioxide, a warming greenhouse gas, to build up in the atmosphere again. This part of the carbon cycle has helped Earth recover from past ice ages and avoid runaway warming.

Even as the sun has gradually brightened, this cycle has contributed to keeping temperatures on Earth within a range where liquid water and life can persist for long spans of time.

Now, scientists are asking whether similar geological processes might operate on other planets, and if so, how they might detect them. For example, if researchers could observe enough rocky planets in their stars' habitable zones, they could look for a pattern connecting the amount of sunlight a planet receives and how much carbon dioxide is in its atmosphere. Finding such a pattern may hint that the same kind of carbon-cycling process could be operating elsewhere.

The mix of gases in a planet's atmosphere is shaped by whats happening on or below its surface. One study shows that measuring atmospheric carbon dioxide in a number of rocky planets could reveal whether their surfaces are broken into a number of moving plates, like Earth's, or if their crusts are more rigid. On Earth, these shifting plates drive volcanism and rock weathering, which are key to carbon cycling.

Keeping an eye on distant atmospheres

The next step will be toward gaining a population-level perspective of planets in their stars' habitable zones. By analyzing atmospheric data from many rocky planets, researchers can look for trends that reveal the influence of underlying planetary processes, such as the carbon cycle.

Scientists could then compare these patterns with a planet's position in the habitable zone. Doing so would allow them to test whether the zone accurately predicts where habitable conditions are possible, or whether some planets maintain conditions suitable for liquid water beyond the zone’s edges.

This kind of approach is especially important given the diversity of exoplanets. Many exoplanets fall into categories that don't exist in our solar system — such as super Earths and mini Neptunes. Others orbit stars smaller and cooler than the sun.

The datasets needed to explore and understand this diversity are just on the horizon. NASA's upcoming Habitable Worlds Observatory will be the first space telescope designed specifically to search for signs of habitability and life on planets orbiting other stars. It will directly image Earth-sized planets around sun-like stars to study their atmospheres in detail.

Instruments on the observatory will analyze starlight passing through these atmospheres to detect gases like carbon dioxide, methane, water vapor and oxygen. As starlight filters through a planet's atmosphere, different molecules absorb specific wavelengths of light, leaving behind a chemical fingerprint that reveals which gases are present. These compounds offer insight into the processes shaping these worlds.

The Habitable Worlds Observatory is under active scientific and engineering development, with a potential launch targeted for the 2040s. Combined with today's telescopes, which are increasingly capable of observing atmospheres of Earth-sized worlds, scientists may soon be able to determine whether the same planetary processes that regulate Earth’s climate are common throughout the galaxy, or uniquely our own.

Binary star system Eta Cassiopeiae, located just 19 light-years away, could be a good target in the search for habitable exoplanets, according to a recent study. University of California, Riverside astronomer Stephen Kane and his colleagues simulated the orbital dynamics of the star system and concluded that it's not home to any giant planets – or any planets farther than 8 astronomical units (8 times Earth's distance from the Sun) away from its main star.

But small, Earth-like planets might still be hanging out in the main star's habitable zone, waiting for astronomers to find them.

An empty planetary neighborhood

From Earth, Eta Cassiopeiae looks like a bright point of light in the night sky, but it's really two stars locked together in an endless orbital waltz, circling a shared center of gravity once every 472 years. The larger of the pair is a G-type star just a smidgen more massive than our sun, and its smaller partner is a K-type star which weighs in at just 57% of our sun's mass.

Recently, the European Space Agency's Gaia mission provided astronomers with much more precise measurements of the two stars’ masses and orbits. Kane and his colleagues used that data, along with new observations from a high-resolution spectrometer at the Keck Observatory, to build computer simulations of the star system.

It turns out that the outer reaches of the star system are probably pretty empty. The team of astronomers simulated the orbits of hypothetical planets orbiting Eta Cassiopeiae A, the larger of the two stars, and they found that planets orbiting farther than 8 astronomical units away were just too vulnerable to getting pushed and pulled around by Eta Cassiopeiae B – and ending up in wildly unstable orbits. All of those simulated outer worlds got kicked out of the star system to begin new lives as rogue planets, leaving the outer reaches of the Eta Cas system eerily vacant.

"Inside of 8 AU, the situation is more complicated," wrote Kane and his colleagues in their recent paper.

The enormous mass of Eta Cassiopeiae B makes itself felt even close to the larger star; some of the simulated planets got nudged into long, narrow eccentric orbits even when they started in about the same position as Mars. But despite that, most of the planets in the larger star's habitable zone ended up on stable orbits (even if some of those orbits were eccentric ones, which might have caused some wild seasonal swings on the planets’ surfaces). That raises the intriguing possibility that the real Eta Cassiopeiae A might have some Earth-sized worlds orbiting in its habitable zone.

Kane and his colleagues say it's definitely worth a look with future telescopes like the European Southern Observatory's Extremely Large Telescope. As we speak, astronomers are working to pinpoint — and rule out — star systems where newer, bigger telescopes might capture direct images of potentially habitable worlds. Eta Cassiopeiae might be one of those star systems, if Kane and his colleagues are right.

Complicated, But not impossible

One of the things that makes Eta Cassiopeiae so interesting for future exoplanet searches is that, according to Kane and his colleagues’ recent study, the system has no giant planets at all: no alien versions of Uranus or Neptune on the outskirts of the system, and no hot Jupiters whizzing dangerously close to the main star, either. In their simulations, Kane and his colleagues modeled whether today’s telescopes could detect giant planets, orbiting Eta Cassiopeiae A at various distances, using the radial velocity method. (Radial velocity looks for slight wobbles in a star that reveal the gravitational pull of an orbiting planet.)

If any giant planets orbited Eta Cassiopeiae A within about 8 AU, astronomers could spot their telltale signature in the spectrum of light from the star. And since no planets at all can survive the binary star system’s constantly-shifting gravity beyond 8 AU, the system must be totally giantless.

That may actually be good news for life, or at least for the presence of planets in the habitable zone around Eta Cassiopeiae A. If there were giant planets orbiting the larger star, their orbits would be as eccentric as those of comets in our own solar system – and having a gas giant swooping through the inner star system every few decades or centuries would be a nightmare for rocky little worlds just trying to stay in their orbital lanes. It would, in Kane and his colleagues’ words, "effectively eliminate these systems as viable search targets for habitable zone terrestrial planets."

There's no guarantee that Eta Cassiopeiae is home to any potentially habitable planets, or even any planets at all, but Kane and his colleagues' recent study suggests it could be worth a look.

Kane and his colleagues published their work in October in The Astronomical Journal.

Researchers at Cornell University have developed the first-ever reflectance spectra — essentially a color-coded key — of the colorful microorganisms that live in Earth's clouds. Now, astronomers can potentially use this key to identify similar organisms in the clouds of exoplanets, if they exist.

"We thought clouds would hide life from us, but surprisingly, they could help us find life," Lisa Kaltenegger, professor of astronomy at Cornell and the director of the Carl Sagan Institute, said in a statement.

The idea for the work came from astrobiologist Ligia Coelho, an astronomy postdoctoral fellow at Cornell University. "There is a vibrant community of microorganisms in our atmosphere that produces colorful biopigments, which have fascinated biologists for years. I thought astronomers should know about them," she said.

Biopigments are quite common in Earth's organisms. "Biopigments have a universal character on our planet. They give us tools to fight stresses like radiation, dryness and lack of resources," said Coelho. "We produce them, and so do bacteria, archaea, algae, plants, other animals." The cloud microorganisms produce biopigments for protection from ultraviolet rays, which are abundant high in the atmosphere where they reside.

Running the spectra through models, Coelho and her collaborators determined that exoplanet clouds with the colorful microorganisms would look different from exoplanet clouds without them. Thus, astronomers can use them as a potential biosignature.

Of course, we don't know that similar microorganisms even exist anywhere else in the universe. But if they do, we'll be able to use upcoming telescopes like NASA's Habitable Worlds Observatory and the European Southern Observatory’s Extremely Large Telescope to look for them.

"Finding colorful life in Earth’s atmosphere has opened a completely new possibility for finding life on other planets," said Kaltenegger. "Now, we have a chance to uncover life even if the sky is filled with clouds on exoplanets."

Research on the biopigment spectra was published in the Astrophysical Journal Letters on Nov. 11.

Scientists use TESS to hunt for extrasolar planets, or "exoplanets," by observing the dips in starlight they cause as they cross or "transit" the face of their star from its viewing angle around Earth. Beginning with almost half a million planetary systems, a team of researchers worked this down to a sample of 15,000 possible planetary signals detected by TESS. The team then applied a computer algorithm that helped them identify only those planet candidates that orbit stars just beginning to become red giants, finding the number to be around 130, including 33 that were new candidates detected for the first time.

This revealed that planets are much less likely to be found orbiting close to a red giant star, implying that many planets get wiped out when their stars undergo the transformation into a red giant.

"This is strong evidence that as stars evolve off their main sequence, they can quickly cause planets to spiral into them and be destroyed. This has been the subject of debate and theory for some time, but now we can see the impact of this directly and measure it at the level of a large population of stars," Edward Bryant, team member and University of Warwick researcher, said in a statement. "We expected to see this effect, but we were still surprised by just how efficient these stars seem to be at engulfing their close planets."

Stars make an extreme makeover

Stars become red giants when they reach the end of the hydrogen in their cores, meaning this lightest element can't continue to be converted into helium, the nuclear process known as fusion that powers so-called "main sequence" stars like the sun. When this happens, the cores of these stars start to contract, but the outer layers, where hydrogen is still transformed to helium, "puff out," causing the star to expand to as much as 1,000 times its original size. That marks the end of the main sequence phase and the beginning of the red giant stage of a star's life.

Obviously, this is bad news for the planets orbiting close to this transforming star. For example, when the sun enters its red giant phase in around 5 billion years, it will expand to swallow Mercury and Venus, and possibly even our own planet. However, this isn't the only method of destruction that this team thinks stars employ as red giants.

"We think the destruction happens because of the gravitational tug-of-war between the planet and the star, called tidal interaction. As the star evolves and expands, this interaction becomes stronger," Bryant continued. "Just like the moon pulls on Earth’s oceans to create tides, the planet pulls on the star. These interactions slow the planet down and cause its orbit to shrink, making it spiral inwards until it either breaks apart or falls into the star."

This is reflected by the fact that when the team focused on stars that had already begun to expand, there was only a 0.11% chance of them hosting a planet. That is around 3% lower than the chance of a main-sequence star hosting a planet. The researchers also found that the chance of a red giant hosting a giant planet such as Jupiter or Saturn also fell as the age of the star increased.

But what does this tell us about Earth's chances of surviving the sun's metamorphosis into a red giant?

"Earth is certainly safer than the giant planets in our study, which are much closer to their star. But we only looked at the earliest part of the post-main sequence phase, the first one or two million years of it – the stars have a lot more evolution to go," Vincent Van Eylen, team member and University College of London researcher, said. "Unlike the missing giant planets in our study, Earth itself might survive the sun’s red giant phase. But life on Earth probably would not."

The researchers will now search for more data in order to better understand why some planets become prey for elderly stars and others do not, which could answer questions about Earth's potential survival.

"Once we have these planets’ masses, that will help us understand exactly what is causing these planets to spiral in and be destroyed," Bryant concluded.

The team's research was published in the October edition of the Monthly Notices of the Royal Astronomical Society.

Using the James Webb Space Telescope, researchers applied a new technique called 3D eclipse mapping, or spectroscopic eclipse mapping, to track subtle changes in various light wavelengths as WASP-18b moved behind its star. These variations allowed scientists to reconstruct temperature across latitudes, longitudes and altitudes, revealing distinct temperature zones throughout the planet's atmosphere.

"If you build a map at a wavelength that water absorbs, you'll see the water deck in the atmosphere, whereas a wavelength that water does not absorb will probe deeper," Ryan Challener, a postdoctoral associate in Cornell’s Department of Astronomy and lead author of a study published on the research, said in a statement. "If you put those together, you can get a 3D map of the temperatures in this atmosphere."

WASP-18b is located about 400 light-years from Earth; it has roughly 10 times Jupiter's mass and completes an orbit of its host star in just 23 hours. Because it's so close to its star, temperatures in the planet's atmosphere reach nearly 5,000 degrees Fahrenheit (2,760 degrees Celsius). Those scorching conditions made it an ideal candidate for testing the new method of 3D temperature mapping.

The map revealed a bright central hotspot surrounded by a cooler ring on the planet's dayside — it has a tidally locked orbit, meaning that one side of the planet is always facing its star — demonstrating that the exoplanet's winds fail to distribute heat evenly across the atmosphere.

Remarkably, the hotspot showed lower water vapor levels than WASP-18b's atmospheric average. "We think that's evidence that the planet is so hot in this region that it's starting to break down the water," Challener said. "That had been predicted by theory, but it’s really exciting to actually see this with real observations."

This new 3D eclipse mapping technique will open many doors in exoplanet observations, as it "allows us to image exoplanets that we can't see directly, because their host stars are too bright," said Challener. As 3D eclipse mapping is applied to other exoplanets observed by Webb, "[w]e can start to understand exoplanets in 3D as a population, which is very exciting," he added.

The team's research was published in the journal Nature Astronomy on October 28, 2025.

It has previously been theorized that binary systems are hostile to the formation of complex planetary arrangements, meaning this discovery could change how we think about planet formation and the stability of worlds after formation. What makes the planets of TOI-2267 even more exciting is they also break some previously held exoplanet records.

Furthermore, the binary star nature of this system, located around 190 light-years from Earth, means these exoplanets could experience dual starsets reminiscent of the famous scene in Star Wars: A New Hope in which Luke Skywalker gazes dreamily out at the stars of his homeworld, Tatooine.

"Our analysis shows a unique planetary arrangement: two planets are transiting one star, and the third is transiting its companion star," Sebastián Zúñiga-Fernánde, study team member and a researcher at the University of Liège (ULiège), said in a statement.

"This makes TOI-2267 the first binary system known to host transiting planets around both of its stars."

Record breakers!

Binary star systems come in a range of shapes, sizes and arrangements. TOI-2267 is a "compact binary." This means the stars that comprise this system orbit each other in close proximity. This closeness causes gravitational instability that existing planetary formation models have suggested should result in an environment unsuitable for planet formation.

Yet, planets have formed in TOI-2267.

"Our discovery breaks several records, as it is the most compact and coldest pair of stars with planets known, and it is also the first in which planets have been recorded transiting around both components," Francisco J. Pozuelos, study team co-leader and a researcher at the Instituto de Astrofísica de Andalucía (IAA-CSIC), said in a statement.

Pozuelos and colleagues got their first hints about these three distant Earth-like worlds when they examined data from TESS using their detection software, SHERLOCK. This early indication of planets in the TOI-2267 system prompted the team to get ready for more observations with several other observatories. This included SPECULOOS, a network of robotic telescopes comprised of SPECULOOS Southern Observatory at the Paranal Observatory in Chile and SPECULOOS Northern Observatory at the Teide Observatory in Tenerife, and a pair of telescopes in Belgium called TRAPPIST (Transiting Planets and Planetesimals Small Telescope).

These facilities are specially adapted to investigate small exoplanets around cool and faint stars, meaning they were vital in allowing the team to characterize TOI-2267, and thus, discovering its surprising nature.

"This system is a true natural laboratory for understanding how rocky planets can emerge and survive under extreme dynamical conditions, where we previously thought their stability would be compromised," Pozuelos said.

The queries raised regarding planet formation by this system could be an investigation that is right in the wheelhouse of the James Webb Space Telescope (JWST) as well as the next generation of ground-based observatories. These instruments should allow astronomers to precisely measure the masses, densities and possibly even the atmospheric chemistry of the newly discovered planets of TOI-2267.

"Discovering three Earth-sized planets in such a compact binary system is a unique opportunity," Zúñiga-Fernández concluded. "It allows us to test the limits of planet formation models in complex environments and to better understand the diversity of possible planetary architectures in our galaxy."

The team's research was published on Friday (Oct. 24) in the journal Astronomy & Astrophysics.

The planet, known as GJ 251c, orbits a red dwarf star 18.2 light-years away in the constellation of Gemini, the Twins. The planet's mass is four times greater than that of Earth, making it a 'super-Earth' — a rocky planet larger and more massive than our own.

"While we can't yet confirm the presence of an atmosphere or life on GJ 251c, the planet represents a promising target for future exploration," said Suvrath Mahadevan, who is a professor of astronomy at Penn State University, said in a statement.

In the habitable zone, sometimes referred to as the Goldilocks zone, conditions are just right for liquid water to exist on the surface of a planet with an appropriate atmosphere.

GJ 251c was discovered thanks to observations spanning over 20 years, during which scientists looked for a slight wobble of the world's parent star incurred by the planet's gravity. As the star wobbles ever so slightly toward and away from us, we see a Doppler shift in its radial velocity that can be measured with a spectrograph.

One other planet is known to exist in the system, GJ 251b, which was discovered in 2020 and orbits its star every 14 days at a distance of 7.6 million miles (12.2 million kilometers). Using archive data from telescopes worldwide, a team of astronomers, including Mahadevan, was able to refine the accuracy of the radial velocity measurements for planet GJ 251b

The team then combined this refined data with brand new, high-precision observations from the Habitable-Zone Planet Finder (HPF), which is a near-infrared spectrograph on the Hobby-Eberly Telescope at McDonald Observatory in Texas. This revealed a second planetary signal belonging to a four-Earth-mass world orbiting the star every 54 days. That was then confirmed by measurements with the NEID spectrograph on the 3.5-meter WIYN telescope at Kitt Peak National Observatory in Arizona.

Though it may sound straightforward, in reality, the challenge of detecting the planet was formidable.

Stars are constantly roiling and churning as convective bubbles burst through to their visible surfaces and prominences splutter into space. This creates a noisy background of what's called asteroseismic activity that manifests as Doppler shifted lines in the star's spectrum. Picking out the Doppler shifted radial velocity signals from this noise is tricky, requiring a great deal of modeling what a planetary signal should look like.

"This is a hard game in terms of trying to beat down stellar activity as well as measuring its subtle signals, teasing out slight signals from what is essentially this frothing, magnetospheric cauldron of a star-surface," said Mahadevan.

Now that we know about the planet, astronomers can plan future observations.

GJ 251c is probably a little bit too far away from its star for the James Webb Space Telescope (JWST) to search for signs of an atmosphere around it. The next generation of 30-meter-class telescopes might be able to detect the planet's atmosphere via a method of searching for light reflected off its surface or atmosphere, but it will likely require the Habitable Worlds Observatory, which is a planned giant space telescope that is hoped to launch in the 2040s, to fully characterize GJ 251c.

"We are at the cutting edge of technology and analysis with this system," said Corey Beard of the University of California, Irvine, who participated in the research. "We need the next generation of telescopes to directly image this candidate."

Although GJ 251c is described by Mahadevan as being "one of the best candidates in the search for an atmospheric signature of life," referencing how we will search for biosignatures in the planet's atmosphere, there remains an elephant in the room: its star.

At 36% of the mass of our sun, the star GJ 251 is a red dwarf. Astronomers have now found numerous rocky planets in the habitable zone of red dwarfs, including Proxima Centauri b, TRAPPIST-1e and f, and Teegarden's Star b. However, red dwarfs are notorious for having violent tempers that bely their diminutive stature, releasing regular powerful flares that can over time strip a planet of its atmosphere. For example, the JWST's observations of the inner three planets of TRAPPIST-1 find no evidence for an atmosphere, while its observations of the fourth planet, e, are so far inconclusive. Some astronomers are now growing skeptical that Earth-like worlds can thrive around red dwarfs.

What GJ 251c has going for it is that it is slightly farther away from its star than habitable zone planets found around other red dwarfs are. This is thanks to its star being a little more massive than those other stars and therefore hotter, pushing the habitable zone farther out. It is possible that GJ 251c is far enough away from its star to have avoided the worst of its temper tantrums, and, if armed with a thick atmosphere and strong planetary magnetic field, it could have resisted the star's stellar wind from stripping its atmosphere away.

However, at present, this remains guesswork. "We made an exciting discovery," said Mahadevan, "But there’s still much more to learn about this planet."

The findings were reported on Oct. 23 in The Astronomical Journal.

Scientists spotted the heavy water (which we'll get into in just a moment) in the planet-forming disk of gas and dust around the young star V883 Orionis by ALMA, the Atacama Large Millimeter/submillimeter Array, which is a network of 66 radio dishes in Chile. V883 Ori is located 1,350 light-years away and is a member of a cluster of stars born out of the famous Orion Nebula.

Now, here's what heavy water is.

Ordinary water is formed of two atoms of hydrogen and one atom of oxygen. Hydrogen is made from a single proton orbited by an electron. However, the nuclei of some atoms of hydrogen feature one proton and one neutron, too. We describe atoms with extra neutrons as an isotope of that element, and the isotope of hydrogen with one neutron is called deuterium. Its atomic mass is slightly higher than regular hydrogen, thanks to that extra neutron.

Heavy water, therefore, supplants its two regular hydrogen atoms with two deuterium atoms. We have heavy water in our own solar system, found for example in comets — and the ratio of heavy water to ordinary water in a cometary body can tell us about its formation history.

"Until now, we weren't sure if most of the water in comets and planets formed fresh in young disks like V8783 Ori, or if it is pristine, originating from ancient interstellar clouds," said John Tobin of the National Radio Astronomy Observatory in the United States in a statement.

The ALMA observations provided the answer. Violent shocks and outbursts from young stars destroys heavy water in a planet-forming disk, allowing it to reform as regular water. If this had happened around V883 Ori, the ratio of heavy water to regular water would be low, similar to what we find in our solar system.

Instead, however, the ratio as measured by ALMA in V883 Ori's disk is the same as what is observed in clumps of molecular gas before they have formed stars or planets. In fact, the ratio is two orders of magnitude higher than what it would be if the water had been broken apart and reformed in the disk.

"Our detection indisputably demonstrates that the water seen in this planet-forming disk must be older than the central star and formed at the earliest stages of star- and planet-formation," said Margot Leemker, of the University of Milan, who led the study. "This presents a major breakthrough in understanding the journey of water through planet formation, and how this water made its way to our solar system and possibly Earth, through similar processes."

This means the water is older than the star — it could actually be billions of years older, having sat in the molecular cloud that became the Orion Nebula all that time as ice coating tiny dust grains.

V883 Ori is only half a million years old, and water was first detected in its circumstellar planet-forming disk in 2023. No planets have yet been detected in that disk, although any comets that may have formed already will mirror this high ratio of heavy water. The star's young age means there hasn’t been enough time yet for its ancient water to have been reprocessed by heating in the disk, but that time will soon come, as outbursts from the young star have already been observed — for example, in 2016, when ALMA studied the outburst's effect on the snow line, or where water turns from vapor to ice, in V883 Ori’s disk.

"The detection of heavy water … proves the water's ancient heritage and provides a missing link between clouds, disks, comets and ultimately planets," said Tobin. "This finding is the first direct evidence of water’s interstellar journey from clouds to the materials that form planetary systems — unchanged and intact."

The results were published on Oct. 15 in the journal Nature Astronomy.

The Mauve telescope, developed by London-headquartered start-up Blue Skies Space, is the size of a small suitcase and carries an off-the-shelf ultraviolet spectrometer modified to monitor flaring stars. It is one of the payloads that will launch on SpaceX's upcoming Transporter-15 mission, currently set for no earlier than November 2025.

Just like our sun, other stars in the universe produce flares — flashes of high-energy radiation from the dark, magnetically dense regions known as sunspots. Each flare sends a wave of energetic particles into the star's surroundings. When such a wave washes over Earth, the radiation, consisting of X-ray and extreme ultraviolet light, interferes with radio transmissions, causing blackouts. The flare also disturbs the ionosphere — the electrically charged layer of Earth's atmosphere at altitudes above 20 miles. This interference affects the accuracy of the navigation and positioning signal from satellites such as the U.S. GPS system.

But the sun is not a very active star. Research suggests that many of its siblings are much more temperamental. The bursts of radiation that some stars produce are so intense and so frequent that they virtually sear any object in their vicinity, preventing any possible life from emerging. By tracking the flaring of hundreds of stars, Mauve will help astronomers pick out those that are more likely to host habitable exoplanets.

"Mauve will allow us to understand the behavior of stars when they are emitting large amounts of energy," Marcell Tessenyi, the founder and CEO of Blue Skies Space, told Space.com. "It will also help us understand what sort of impacts these stars might have on their neighboring planets. We will be able to understand which stars are likely to be damaging for a life environment and which would be benign."

The last dedicated mission to observe stellar ultraviolet light, the International Ultraviolet Explorer, ended in 1996. The legendary Hubble Space Telescope can perform such measurements, but availability of observing time is limited, Tessenyi said. Hundreds of science teams from all over the world compete for observing time on the veteran space telescope, pursuing a multitude of challenging astronomical research projects that can't be accomplished by any other star-watching machine.

Since scientific interest in exoplanets is on the rise, Blue Skies Space decided to cover the increasing demand for observations of stellar flares with a small, low-cost telescope and sell the resulting data to scientists worldwide through a yearly subscription model.

"The space agencies do a fantastic job at delivering very high-quality space telescopes, but sometimes it can take a long time," Tessenyi said. "And when these satellites are operational, like the Hubble Space Telescope or James Webb, people have to apply and hope they get the observing time they need. But not all science requires a very large and complicated satellite."

With the low-cost Mauve (the company refused to disclose the exact cost of the mission), Blue Skies Space is pioneering a new approach to astronomical research from space. Although the new commercial space ethos of building satellites fast and cheap has dominated Earth imaging from space for years, deep-space astronomy has so far been headed mostly in the opposite direction — trending toward more complex machines worth billions of dollars.

Mauve, built in less than three years, is Blue Skies Space's first satellite to launch, although it was conceived after another mission, called Twinkle, which is still in the works. Twinkle, expected to make it to space later this decade, is a larger satellite, weighing 330 pounds (150 kilograms in mass) and carrying an 18-inch (45 cm) telescope. Like Mauve, Twinkle will look for exoplanets around nearby stars and gather information about their chemical composition. But Mauve, Tessenyi said, will help the researchers zoom in on the most promising stellar systems, to make Twinkle's work easier.

Tessenyi said that despite initial scepticism among scientists whether the new space way could work for astronomy, Blue Skies Space has seen a lot of interest in both of their missions. Nineteen universities from all over the world have already signed up for the data, which will begin streaming to Earth early next year.

Mauve will orbit Earth at an altitude of 310 miles (500 kilometers) for at least three years. If the project is successful, Blue Skies Space might add more satellites to its fleet in the future. The company is already studying a concept of a successor to Mauve, a more potent UV-observer Mauve+.

"We finance the satellites upfront, put them into space, and once the mission is operational, we make data available to users and over time we recover the cost of the construction and operations," Tessenyi said. "If the satellite is a success and we make a surplus, we reinvest that into our subsequent satellites and we grow the company to deliver more satellites using this model."

This strange world, which sits about 578 light-years from the solar system, breaks almost every known rule for how planets should behave. First off, it orbits a very young star that's just 700 million years old, making it one of the youngest planetary systems ever discovered. The planet is 9x wider than Earth, but only 30 times its mass. That means it's as wide as Jupiter but less than a tenth of its mass, a very light planet. This odd combination of large size and small mass classifies TOI-4507 b as a "super-puff" — an exoplanet with a large, extended atmosphere.

Second, TOI-4507 b is on a nearly polar orbit; it swings around its star almost perfectly perpendicular to the star's rotation. It has a relatively close orbit, completing an entire revolution in just 105 days — but this also makes it one of the longest-period super-puffs ever found. So we have a low-density, puffy planet orbiting relatively far from a young star in a nearly perpendicular orbit. What's going on?

With TOI-4507 b, there are more mysteries than answers. But the researchers who revealed the discovery of the planet ruled out some possibilities. In a pre-print study that has yet to be peer-reviewed and submitted to arXiv, they used a combination of data from NASA's Transiting Exoplanet Survey Satellite and ASTEP, a planet-hunting telescope in Antarctica.

Many super-puffs get their inflated atmospheres from tidal heating. If a planet orbits close to its star in an elliptical orbit, then its interior will stretch and squeeze as the gravitational strength of the star changes. This kind of tidal heating leads to the molten cores and liquid oceans of many moons in the outer solar system, and in other systems, it can heat up a planet, giving it an extended atmosphere.

But TOI-4507 b is too far from its star for tidal heating to play a significant role.

So perhaps it's not as big as we think it is. Some planets may have large ring systems that block light just as easily as a planet can, leading to the appearance of large planetary bodies. But while TOI-4507 b is relatively cold, it's not cold enough to support a ring system for very long.

Plus, something dramatic must have happened in this planet's past. This event might have been quick and catastrophic, causing a misalignment of the protoplanetary disk with the star. Or it might have been slow and steady — for example, if another planet orbiting much farther out were tugging it into a new orbit.

All of these mysteries make TOI-4507 b ripe for follow-up studies. Because of its brightness and the low density of its atmosphere, TOI-4507 b makes a great candidate for observations with the James Webb Space Telescope, which should have the capabilities to determine what this mysterious planet's atmosphere is made of — and hopefully unlock some more clues as to how this strange super-puff came to be.

The problem with Uranus and Neptune is that we have extremely little data available to us. Unlike Jupiter and Saturn, both of which have received dedicated missions like the Cassini probe and the Juno spacecraft, the outer planets have not received any visitors since the Voyager 2 flybys more than 30 years ago.

So, to build an understanding of these planets' interiors, we must rely on a variety of indirect clues, like their magnetic fields, observations of surface atmosphere features, and subtle changes in the orbits of their moons. For decades, models of solar system formation dictated that the outer realms of the solar system were dominated by molecules like water and ammonia ice. So naturally, those compounds would make up the bulk of Uranus and Neptune, hence their "ice giant" moniker.

But a new pre-print study accepted for publication in the journal Astronomy and Astrophysics took a completely different approach. Instead of trying to build a physical model of planetary interiors from possibly flawed and biased assumptions, the authors generated a series of random models of the interior contents of Uranus and Neptune. Then, they compared those random models to a host of observational data and built a database of all models compatible with observations.

The models yielded a few expected results. Each planet is less than a quarter hydrogen and helium, which matches predictions from solar system formation models and the observed densities of the planets. The models also created layers of electrically conductive material, which can explain the magnetic fields of Uranus and Neptune.

But this agnostic approach did yield one major surprise: We may not have any idea what the interiors of Uranus and Neptune are really like.

For example, the rock-to-water ratio for Uranus varies widely, anywhere from a low of 0.04, meaning the planet is almost entirely water, to as much as 3.92, which is the complete opposite. Neptune is slightly better understood, but it could still have anywhere from as much as five times as much water as rock up to twice as much rock as water.

If that's the case, then "ice giants" may be the wrong name for these planets. Most of their bulk could be in the form of rock, potentially giving them more rocky material than even Jupiter or Saturn, even though Neptune and Uranus are much smaller than those two gas giants.

If this idea holds up, it could challenge existing models of solar system formation, as we would have to figure out a way to get enough rocky material into the outer solar system to let it accumulate onto these planets.

Only a dedicated mission to Uranus or Neptune could resolve these issues, as we need high-quality data from an orbiter to fully understand what's going on.

Using the Magellan Telescope in Chile and the Large Binocular Telescope in Arizona, astronomers have captured a striking new view of a protoplanet named WISPIT 2b — a gas giant in its infancy estimated to be about five times more massive than Jupiter and just five million years old. The baby planet can be seen within a ring-shaped gap in the dusty disk surrounding its young parent star, named WISPIT 2, as it gathers material to grow into a fully realized planet.

The new image marks the first direct evidence of a growing planet observed within the very ring gap that it's shaping, confirming a longstanding prediction of how gas giants form, according to a statement from NASA.

WISPIT 2b orbits a star about 437 light-years from Earth. The disk of gas and dust, or "protoplanetary disk," that surrounds a young star functions as the birthplace for new planets. It has been suggested that gaps or clearings within these disks can be created by growing planets as they scatter material outwards.

WISPIT 2b was first detected using the European Southern Observatory's Very Large Telescope Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (VLT-SPHERE) in northern Chile, which initially revealed ringlike bands and a conspicuous gap that hinted at the protoplanet's activity.

Now, using Magellan's MagAO-X extreme adaptive optics system, astronomers have detected the faint glow of H-alpha light — the spectral fingerprint of hydrogen gas heating up as it falls onto a forming planet. Meanwhile, observations from the Large Binocular Telescope's infrared cameras captured WISPIT 2b in the same spot, helping to confirm that the emission came from an actively accreting planet rather than another source, according to the statement.

In the recent image shared by NASA, the protoplanet WISPIT 2b is a small purple dot to the right of a bright white ring of dust surrounding the system's parent star. A fainter white ring outside of WISPIT 2b can also be seen.

The position of WISPIT 2b inside the disk's gap suggests that it is not merely passing through but shaping its surroundings, sweeping up material and pushing dust aside as it grows. Astronomers even spotted a faint second source in another, inner ring gap that could mark a sibling world in formation.

Their findings from MagAO-X were published Aug. 26 in The Astrophysical Journal Letters, alongside another study published the same day using observations from the VLT-SPHERE instrument.

"We've found 6,000 planets, but none of them are like Earth," said Aurora Kesseli, an astronomer at Caltech who works on NASA's Exoplanet Archive keeping a tally of the worlds already discovered, in an interview with Space.com. "So when people ask why we are still looking for exoplanets when we have found 6,000 of them, it's because we haven't found an Earth-like planet yet. But there are a lot of the upcoming missions that are really tuned-in to try and find something that actually looks like Earth."

Several new planet-finding missions are on the cusp of being launched. First to go into space will be the European Space Agency's PLATO (PLAnetary Transits and Oscillations of stars), currently set to launch in December 2026 on a mission to search for the transits of planets including rocky, Earth-sized worlds in the habitable zone of their star.

A year later, NASA's Nancy Grace Roman Space Telescope will blast off for the L2 Lagrange point alongside PLATO and the James Webb Space Telescope (JWST). Although a multi-purpose space telescope, it will hunt for planets made visible by gravitational microlensing.

Then, in 2028, the China National Space Administration plans to launch the Earth 2.0 mission, which will also head to the Lagrange 2 point to search for planetary transits of Earth-like planets around sun-like stars.

With all three missions on the go at the same, and with NASA's TESS (Transiting Exoplanet Survey Satellite) still in operation, there will soon be a flood of new exoplanet discoveries, and Kesseli and her colleagues at the Exoplanet Archive are going to have to figure out how to collate all the data.

"The challenge for the Archive is definitely going to be handling the sheer numbers of exoplanets still to come, from PLATO, from Earth 2.0, from NASA's Roman Space Telescope," she said. "We're expecting on the order of 100,000 transiting planet candidates from those missions."

While these will only be candidates that will need to be verified, either through statistical methods or by determining their mass via radial velocity measurements, the current total of 6,022 exoplanets (as of the beginning of October) will soon increase dramatically. In fact, it could increase by a few thousand by as early as the end of 2026. That's when scientists working on the European Space Agency's Gaia mission, which carefully measures the position and properties of a billion stars, will release their catalogue of exoplanet candidates discovered via a technique known as astrometry, which relates to the position and motion of stars.

"Their first delivery of exoplanets is going to be in December 2026, and they are expecting a few thousand candidates," said Kesseli of the impending Gaia findings.

In the radial-velocity detection technique, with which 51 Pegasi b, the first planet known to orbit a sun-like star, was found, astronomers measure the Doppler shift of a star's subtle motion towards and away from us as it revolves around a center of mass shared with its orbiting planet(s). With astrometry, instead of measuring the radial motion of a star, astronomers measure its tangential motion on the sky as it is pulled in different directions by orbiting planets.

"So far we have less than 10 planets that have been discovered by astrometry," said Kesseli. That's because the measurements are difficult to make, the tangential motion being rather small. Gaia, however, is the most sensitive astrometric survey ever performed and will dramatically increase the number of exoplanets found through astrometry. However, most of these planets are likely to be gas giants, since less massive planets will have less gravitational pull on their star, leading to a much smaller tangential motion.

More sensitive to Earth-like worlds will be the Roman Space Telescope. Its 2.4-meter mirror is equipped to conduct wide-field surveys as opposed to the narrow field of view of the similarly sized but differently shaped mirror of the Hubble Space Telescope. As it gazes towards the center of our Milky Way galaxy, Roman will see countless stars in its field of view, enough to even the odds of seeing a microlensing event.

Microlensing is gravitational lensing on a small scale. We're used to seeing the arcs and rings of light belonging to the distorted images of galaxies magnified and warped by the mass of a giant galaxy, or galaxy cluster. However, planets can also bend space enough to lens the light of background stars. The alignment has to be perfect to enable this, and that alignment is only maintained for a brief period, but by watching many millions of stars at the same time, Roman is expected to come up trumps.

"From Roman we are going to get around 2,000 microlensing planets," said Kesseli.

Unfortunately, we will be unable to follow up on these planets once the planet and background star have moved out of alignment from our point of view. Part of the reason is that the vast majority of these planets will be very distant. "They will be far away, in the galactic bulge," said Kesseli.

The main reason, though, is that at no point during the microlensing event do we actually see the planet, or even the star that it orbits, which will usually be too faint to be seen. All we will see is a background star brightening briefly as its light is lensed first by the foreground star and then by the planet accompanying that foreground star. The more massive the planet, the brighter the lensed star becomes, and the bigger the gap between the brightening caused by the foreground star and then by the planet, the farther out the planet must be from its star. Indeed, the technique is particularly sensitive to planets far from their star, including Earth-like planets in the habitable zone.

The microlensing events should provide some statistics of how abundant Earth-sized planets in the habitable zone of sun-like stars are. However, to learn more about such worlds, astronomers will need to find one closer to home so that they can target it with their telescopes.

"Exoplanet characterization and studying exoplanet atmospheres is what I'm most excited about," said Kesseli. In fact, studying the atmospheres of exoplanets via a method called transit spectroscopy is Kesseli's specialty. With this method, a telescope such as the JWST can detect a planet's atmosphere through the way that the light from its star passes through the atmosphere when the planet is transiting. Molecules in the atmosphere absorb some of the star's light at certain wavelengths, leaving a chemical fingerprint on the star's spectrum.

"In the late 2020s ARIEL [Atmosphere Remote-sensing Infrared Exoplanet Large-survey] is going to be launched, which is a European mission to do a census of exoplanet atmospheres," Kesseli continued. "It probably won't do Earth-like planets around sun-like stars, it will mostly be doing Neptune- and Jupiter-sized worlds, but we will get a uniform sample of a thousands planets, so we'll be able to understand what the range in atmospheric conditions looks like, but likely not for rocky planets."

The James Webb Space Telescope is able to study the atmosphere of some nearby habitable-zone planets, but these are orbiting red dwarf stars and not sun-like stars. Red dwarf stars are very different from our sun. They are much smaller and cooler, and their planetary systems are much closer in, leading to tidally locked worlds that always show the same hemisphere to their star. Red dwarfs are also prone to violently flaring and the outpouring of radiation from them can strip an atmosphere clean off a planet.

So far the JWST has searched for an atmosphere around a handful of these planets including some of the worlds belonging to the TRAPPIST-1 system. While no atmospheres around these rocky planets have been discovered so far, Kesseli is not down-hearted.

"So far with JWST it is inconclusive," she said. "With more data, better techniques, more hours on targets like this, I think that we will start to have an idea about which planets likely host atmospheres and which ones don't. But JWST is not going to be able to look at the atmosphere of an exoplanet around a sun-like star, it just doesn't have the sensitivity for that."

Kesseli doubts that even the forthcoming class of 30-meter scale ground-based observatories will be able to detect the atmosphere of an Earth-like planet around a sun-like star. "It's really hard to do Earth-like planets around sun-like stars unless you're doing direct light," she said.

Instead, a whole new telescope, one designed specifically for the job, is required.

"If we want to see an actual Earth-like planet around a sun-like star, the best thing is going to be the Habitable Worlds Observatory, which will be launched in the 2040s," said Kesseli.

The Habitable Worlds Observatory, or HabEx for short, is NASA's next planned space telescope, championed by the National Academy of Science's Decadal Survey. At minimum it would feature an eight-meter telescope mirror, larger than JWST's 6.5-meter mirror, and a coronagraph in the form of a star-shade to block out the light of the host star so that HabEx can see the planet directly. Any planet that it images will still look like a point of light, but the spectrum of that point of light could reveal whether the planet has oceans, continents, vegetation, animal life or even cities.

The first 30 years of exoplanet science focused on discovery and of finding as many planets of all different types as possible so that scientists could draw up statistics for how common each type of planet is. Think of it as a census. And while that process of discovery is going to continue, the next 30 years are going to move increasingly into characterization as we get closer to our stated goal of finding another Earth-like planet truly capable of supporting life.

Perhaps that discovery will come in about 30 years' time courtesy of HabEx, and in turn that could set the tone for the 30 years that follow that, as we continue to reconfigure Earth's, and our, place in the cosmos.

The discovery of 51 Pegasi b was a turning point in astronomical history. No longer were we confined to studying just the planets in our own solar system; there was an entire universe of planetary systems out there for us to explore.

"When the first exoplanet was discovered, I remember thinking that it was really cool, but also thinking, 'Duh! Like, of course there are planets out there!'" said Amanda Hendrix, the director of the Planetary Science Institute in Arizona, in an interview with Space.com.

That first exoplanet proved to be the vanguard for an entire galaxy stuffed to the brim with planets. Today, the exoplanet count stands at more than 6,000 and is growing all the time. The statistics suggest that almost every star of the approximately 200 billion stars in our Milky Way galaxy has planets.

That means there are a lot of planets out there, but 51 Pegasi b was the first. Like most exoplanets, it was found indirectly. Astronomers Michel Mayor and Didier Queloz of the University of Geneva had been searching for planetary systems with ELODIE, a spectrograph on the 1.9-meter (6.2 feet) telescope at the Observatoire de Haute-Provence in France. ELODIE worked by being able to detect a star wobbling.

Why would a planet make a star wobble? Imagine a parent and child sitting on opposite ends of a long seesaw. The parent, being larger, has most of the mass, and the center of the combined mass of both parent and child is therefore much closer to the parent. That's why, with parent and child at either end, the seesaw tips in the direction of the adult.

Suppose, though, that they want to make the seesaw balance horizontally. The parent would shift themselves closer to the pivot point, moving the center of mass closer to the pivot. Once the center of their combined mass falls onto the pivot, the seesaw balances.

This is, in effect, what we see in exoplanetary systems. Just as in the example of the seesaw, the star is located very close to the center of mass because it contains the vast majority of the mass in the system. Often, the center of mass is inside the star, but crucially it is offset and not at its center.

The planet doesn't really orbit the star; it is orbiting the center of mass instead. And vice versa: The star also orbits the center of mass, so it appears to wobble around this point, and in doing so, it will periodically shift closer to us and then away from us. This movement is marginal, but it results in a Doppler shift in the star's light — as the star swings in our direction, its light waves bunch up, shortening their wavelength, and when it swings away from us, the light waves are more stretched out. It's the same effect as in the case of sound waves that change in pitch as they blare out from the siren of a passing emergency vehicle. The more massive the planet and the closer it is to its star, the stronger the shift.

Mayor and Queloz discovered 51 Pegasi b by using ELODIE to measure the Doppler shift in its star's light as it wobbled around the centre of mass between it and 51 Pegasi b. Astronomers call this technique the "radial velocity" method because it is measuring the velocity of the star toward and away from us as it wobbles around. Hundreds of planets have been found by this method since, and the existence of thousands more verified through it. So far, no direct image of 51 Pegasi b has been taken; the planet is too far away from Earth (50 light-years) and too close to its star to be seen by even our best telescopes.

Yet there was a twist. Mayor and Queloz had been expecting to find planetary systems with architectures like that of our solar system, with the smaller rocky planets closer to their star and larger gaseous worlds farther away.

So it was a shock when the size of the Doppler shift suggested that 51 Pegasi b is a gas giant practically on the doorstep of its star. It's a kind of planet that we now call a "hot Jupiter," but at the time it left astronomers flummoxed as to how such a remarkable planet could exist. According to models of planetary formation, gas giants couldn't form close to their star. It is a mystery that has since been solved: 51 Pegasi b and other hot Jupiter exoplanets formed farther from their star, but they then migrated toward the star to arrive in their current close orbit.

For Don Pollacco, who is the lead scientist on the European Space Agency's forthcoming planet-finding PLATO mission and a professor of astronomy at the University of Warwick in England, the discovery of 51 Pegasi b is an example of the dangers lurking in allowing our assumptions and scientific biases to blind us to reality.

"Trying to use our Earth and solar system as the example of what exoplanets should be like led to a big surprise," he told Space.com. "The first planets that were discovered were nothing like the planets in our solar system!"

The discovery of the first exoplanet around a sun-like star did not happen by accident. It was a race that Mayor and Queloz won. In second place was a group led by Paul Butler and Geoff Marcy, then at the University of California, Berkeley, who despite not making the first discovery were able to confirm the existence of 51 Pegasi b, which was important for getting the astronomical community to accept such an extraordinary find. Then, in 1996, Butler and Marcy found 70 Virginis b, which was the second exoplanet to be discovered orbiting a sun-like star and was another hot Jupiter.

Although the nature of 51 Pegasi b blew astronomers' minds, the fact that there were exoplanets at all was less shocking. Science fiction has, of course, been portraying exoplanets for decades, and in 1992, radio astronomers Dale Frail and Aleksander Wolszczan discovered planets orbiting a pulsar, the spinning remnant of a massive star that has gone supernova. However, many astronomers more or less dismiss pulsar planets — Pollacco describes them as "freakish" — because they are not thought to have formed like regular planets and are unlikely to be habitable.

For Hendrix, the key to finally discovering exoplanets was in developing instruments that were sensitive enough to detect them.

"It was just a matter of time before we found them," said Hendrix. "I don't want to diminish the excitement of it, but finding exoplanets really was expected; it was just a case of getting our technology up to speed to be able to find them."

For anybody under the age of 30, the concept of a universe in which we didn't know of other planetary systems might seem, pardon the pun, an alien one. Back in the late 1990s, however, it was like seeing science fiction come to life. The discovery of 51 Pegasi b changed the shape of astronomy. The young researchers inspired by that discovery are, today, leading the charge in discovering and characterizing thousands of exoplanets with some of the most expensive telescopes and space missions ever constructed.

"I remember going to two conferences, one after the other, in 1998," recalled Pollacco. "The first was on planetary nebulae, and I was the youngest person there. Straight afterwards I went to an exoplanet conference and I was the oldest person there! It was amazing, because in the planetary nebula conference there were about 60 people, and in the exoplanet one there were 300, so you could just see what was happening."

The wind had changed, and soon exoplanet science would grow into a monster scientific field, one that captures the imagination of astronomers and the public alike. Many types of world have been found, from more hot Jupiters to "mini Neptunes" and tidally locked worlds, to lava planets, super-Earths and worlds that stand a chance of being habitable, although to date no planet like Earth has been identified. That is a discovery that still lies in our future, and if and when it happens, the discoverers will join the names of Mayor and Queloz in the annals of history.

Rogue planets like this one are cosmic drifters — worlds that roam the galaxy untethered, unlike the familiar planets bound to a solar system. Most rogue planets are thought to be cold, silent wanderers. But Cha 1107-7626 is different.

"People may think of planets as quiet and stable worlds, but with this discovery we see that planetary-mass objects freely floating in space can be exciting places," Víctor Almendros-Abad, an astronomer at the Astronomical Observatory of Palermo, National Institute for Astrophysics (INAF), Italy and lead author of the new study in a statement.

For instance, Cha 1107-7626 is not just drifting through interstellar space — it's feeding.

Using the European Southern Observatory's (ESO) Very Large Telescope (VLT), astronomers have caught it pulling in gas and dust at an astonishing rate: six billion tons every single second. Never before has a rogue planet, or any planet, been observed growing this fast.

"This is the strongest accretion episode ever recorded for a planetary-mass object," Almendros-Abad said.

With a mass equivalent to between five and 10 Jupiters, Cha 1107-7626 is one of the lowest-mass free-floating planets known to host a disk and show active accretion. Observations from ESO's VLT and NASA's James Webb Space Telescope (JWST) reveal telltale signs of a rich, evolving system: infrared excess from 4 to 12 microns, silicate features at 10 microns (similar to those in stars and brown dwarfs), hydrocarbon emission lines pointing to a carbon-rich disk, and multiple signatures of ongoing accretion. Together, these make Cha 1107-7626 the clearest case yet of disk-driven growth in a planetary-mass object — a true poster child for how rogue planets can build themselves in the dark.

"The origin of rogue planets remains an open question: are they the lowest-mass objects formed like stars, or giant planets ejected from their birth systems?" wondered the study's co-author Aleks Scholz, an astronomer at the University of St. Andrews in the United Kingdom, in the statement.

Moreover, Cha 1107-7626 isn't growing at a steady pace — it surges. The team used VLT equipped with the X-shooter spectrograph, along with JWST data and archival observations from the VLT's SINFONI instrument, to catch the planet during a "growth spurt," or burst of accretion. By comparing the light it emitted before and during the burst, the team was able to piece together clues about the process.

Cha 1107-7626's violent growth spurt appears to have been fueled by its magnetic field, which is a process previously only observed in stars. Even more surprising, the chemistry of its disk shifted during the burst, with water vapor appearing only while the accretion was underway.

The discovery suggests at least some rogue planets may grow much like stars, since similar bursts of accretion have been seen in stellar nurseries. Detecting these free-floating worlds is notoriously difficult — they're faint and elusive — but that could soon change. With the upcoming Extremely Large Telescope (ELT), equipped with the world's largest mirror and operating under the darkest skies, astronomers will be able to track down more of these lone planets and reveal just how star-like they truly are.

"This discovery blurs the line between stars and planets and gives us a sneak peek into the earliest formation periods of rogue planets," Belinda Damian, an astronomer at the University of St. Andrews, said in the statement.

"The idea that a planetary object can behave like a star is awe-inspiring and invites us to wonder what worlds beyond our own could be like during their nascent stages," ESO astronomer Amelia Bayo said in the statement.

For years, scientists thought these planets, which are larger than Earth but smaller than Neptune, could form far from their stars, sweeping up ice beyond the so-called "snow line." As the planets migrated inward, scientists have thought that ice might melt into oceans hidden beneath hydrogen skies. Such hypothetical worlds were dubbed "Hycean planets," a blend of "hydrogen" and "ocean."

"Our calculations show that this scenario is not possible," Caroline Dorn, an assistant professor of Physics at ETH Zürich in Switzerland who co-led the new study, said in a statement.

The results come just months after high-profile claims about K2-18b, an exoplanet about 124 light-years away, made global headlines as a likely ocean world "teeming with life." A team of scientists studying James Webb Space Telescope (JWST) observations had reported hints of a possible biomarker gas, dimethyl sulfide, on K2-18b — fueling speculation that the planet might be cloaked in a hydrogen-rich atmosphere above a vast global ocean. These are conditions that could potentially support life (as we know it).

But those claims were quickly met with pushback. Independent analyses of the same JWST data suggested the team's evidence for DMS was weak at best, while other experts cautioned that sub-Neptunes may not be ocean-bearing worlds at all, but rather volatile-rich planets wrapped in thick, hostile atmospheres.

In the new study, Dorn and her team modeled how sub-Neptunes evolve during their early lifetimes, when they are thought to be blanketed by hydrogen gas and covered for millions of years by molten rock. Unlike earlier studies, the researchers included chemical interactions between magma and the atmosphere, according to the statement.

Of the 248 model planets the team studied, "there are no distant worlds with massive layers of water where water makes up around 50 percent of the planet's mass, as was previously thought," Dorn said in the statement. "Hycean worlds with 10-90 percent water are therefore very unlikely."

The team found that hydrogen and oxygen — the building blocks of H2O — tend to bind with metals and silicates in the interior, effectively sequestering water deep in the interior. Even planets that began with abundant ice ended up with less than 1.5% of their mass as water near the surface, the new study reports, far less than the tens of percent envisioned for Hycean planets.

"We focus on the major trends and can clearly see in the simulations that the planets have much less water than they originally accumulated," Aaron Werlen, a researcher on Dorn's team at ETH Zürich who co-led the new study, said in the same statement. "The water that actually remains on the surface as H2O is limited to a few per cent at most."

The researchers also found that the most water-rich atmospheres did not appear on planets formed far from their stars, where ice is plentiful, but rather on planets formed closer in. In these cases, water was generated chemically, as hydrogen in the atmosphere reacted with oxygen from the molten rock.

The implications are sobering for astrobiology. If Hycean planets do not exist, the most promising havens for liquid water, and potentially life, may lie on smaller, rocky worlds more akin to Earth.

Still, K2-18b remains a captivating target, scientists say. As a sub-Neptune, a type of planet missing from our own solar system but common across the galaxy, it could reveal fundamental insights into how planetary systems form and why ours turned out the way it did.

The new results also suggest that Earth may not be exceptional, with many distant worlds veiled in similarly modest traces of water.

"The Earth may not be as extraordinary as we think," Dorn said in the statement. "In our study, at least, it appears to be a typical planet."

The research was published on Sept. 18 in The Astrophysical Journal Letters.

The first planets studied by the ATREIDES program, the two worlds of the TOI-421 system, demonstrate misaligned orbits, hinting that this system experienced a more chaotic evolution than our solar system. Studying it could help astronomers figure out why these "hot Neptunes" appear to be so rare in the cosmos, as well as teach us about how planets form elsewhere in the universe.

"The complexity of the exo-Neptunian landscape provides a unique window onto the processes involved in the formation and evolution of planetary systems," ATREIDES Principal Investigator and University of Geneva (UNIGE) researcher Vincent Bourrier said in a statement describing the ATREIDES program.

To understand why this class of extrasolar planet, or "exoplanet," is missing from close orbits around other stars, ATREIDES scientists investigated the TOI-421 planetary system. Located around 244 light-years from Earth, TOI-421 is an orange dwarf or "K-type" star orbited by two exoplanets, TOI-421 b and TOI-421 c. What this investigation revealed is a surprisingly tilted orbital situation in TOI-421 that implies that this system experienced a chaotic history, one which may help explain why hot Neptunes are so rare.

TOI-421 b is a scorching hot sub-Neptune planet with a mass around 7 times that of Earth that orbits its star at a distance equivalent to around 6% of the distance between our planet and the sun. TOI-421 c is larger, with a mass of around 14 times that of Earth, which orbits its star at a distance equivalent to around 12% the distance between Earth and the sun, making it a hot Neptune and putting it in a region adjacent to the Neptunian desert called "the savanna."

"A thorough understanding of the mechanisms that shape the Neptunian desert, savanna, and ridge will provide a better understanding of planetary formation as a whole ... but it's a safe bet that the universe has other surprises in store for us, which will force us to develop new theories," Bourrier said.

Mapping the Neptunian desert

Over the last 10 years of exoplanet observations, the Neptunian desert has become increasingly complex. Areas further out from stars than the Neptunian desert have been found to be more generously populated with Neptune-sized worlds. This more temperate realm with more Neptune-like exoplanets has come to be known as the "savanna" of the Neptunian desert.

Astronomers have also defined a region between the Savanna and the Neptunian desert, which they call the "Neptunian ridge." This region is more densely populated by Neptune-like worlds than both the desert and the savanna. The scientists of the ATREIDES program aim to understand these three distinct regions by identifying the processes that lead to the relative planetary populations.

The team wants to test the hypothesis that the Neptunian landscape is created as a result of the way that planets migrate from their birthplaces to the orbits we observe them in.

Some exiled planets would migrate slowly through the disk of gas and dust that exists in these systems during their infancy. This sedate migration should produce planets in orbits aligned with their star's equator and the orbits of the other planets in their home system. That is similar to the orbits of the planets in the solar system, which are aligned almost to the equatorial plane of the sun.

However, some other planets would be violently thrown from their site of formation via a chaotic process called "high-eccentricity migration." That should result in those planets falling into highly misaligned orbits.

That means the alignment between a star's orbital plane and the orbital plane of its planets is key to investigating this migration hypothesis.

The team can't yet say anything conclusive yet about the Neptunian desert, its neighboring regions, or planetary evolution in general. Many more observations of more planetary systems with hot Neptunes will be needed for that.

However, this research successfully demonstrates the effectiveness of the ATREIDES program and the techniques it has developed and employed.

The team's research was published on Tuesday (Sept. 16) in the journal Astronomy & Astrophysics.

"We're entering the next great chapter of exploration — worlds beyond our imagination," a narrator says in a NASA video about the milestone. "To look for planets that could support life, to find our cosmic neighbors and to remind us the universe still holds worlds waiting to be found."

The news was announced on Wednesday (Sept. 17), which is serendipitously close to the anniversary of when scientists confirmed the existence of the first exoplanet around a sun-like star: 51 Pegasi b. Discovered on Oct. 6, 1995 by astronomers Michel Mayor and Didier Queloz, 51 Pegasi b is a gas giant 0.64 times as massive as Jupiter that sits approximately 50 light-years from where you're sitting. (To be clear, the very first exoplanet discovery fell in 1992, but that one was around a spinning neutron star, or pulsar. And pulsars are pretty wild. 51 Pegasi b was the first more "normal" exoplanet to be identified.) The right thing to do would be to end this paragraph with the 6,000 exoplanet discovery counterpart to 51 Pegasi b, but that's unfortunately not possible.

This brings us to the complexity of NASA's announcement. "Confirmed planets are added to the count on a rolling basis by scientists from around the world, so no single planet is considered the 6,000th entry," the agency said in a statement. "There are more than 8,000 additional candidate planets awaiting confirmation."

In fact, as of writing this article, we're technically at 6,007 exoplanets in NASA's alien world tally. The "new discovery" featured by NASA is the heftily named KMT-2023-BLG-1896L b, a Neptune-like world with a mass equal to about 16.35 Earths. NASA is also responsible for the bulk of those exoplanet finds, with its TESS (Transiting Exoplanet Survey Satellite) count being at 693 and now-retired Kepler Space Telescope having found over 2,600.

And even though it can be written with just a few keystrokes, each member of that 6,007-strong club represents an entire world comparable to the planets of our solar system, which scientists have been scrutinizing for centuries.

There are 2,035 Neptune-like worlds in that count, in reference to exoplanets with similar sizes to our solar system's very own Neptune and Uranus. These tend to have "hydrogen and helium-dominated atmospheres with cores of rock and heavier metals," according to NASA. ("Metals" doesn't necessarily mean metallic elements. Somewhat confusingly, in astronomy, that just refers to elements heavier than hydrogen and helium).

There are 1,984 gas giants (think Jupiter relatives) and 1,761 super-Earths in the court — the latter group is not to be confused with Earth 2.0 candidates. Super-Earths simply refer to exoplanets that are a little larger than Earth but still lighter than planets like Neptune and Uranus.

NASA's exoplanet count further includes 700 "terrestrial planets," or rocky worlds, and maybe most fascinatingly, seven of "unknown" types.

Indeed, breaking those categories down even further would require stretching your brain to a place where you can imagine a two-faced world half-covered in lava, an orb made of diamond that can regrow its atmosphere, one zipping through space at over 1 million mph (1.6 million kph) and the physical embodiment of hell.

"Each of the different types of planets we discover gives us information about the conditions under which planets can form and, ultimately, how common planets like Earth might be, and where we should be looking for them," Dawn Gelino, head of NASA's Exoplanet Exploration Program, located at the agency's Jet Propulsion Laboratory in Southern California, said in a statement. "If we want to find out if we’re alone in the universe, all of this knowledge is essential."

Still, in the agency's video about the milestone, an existential aspect of exoplanet-hunting is mentioned. "There's one we haven't found — a planet just like ours."

At least, not yet."

A new study presented by professor Susanne Pfalzner of Forschungszentrum Jülich at the Joint Meeting of the Europlanet Science Congress and the Division of Planetary Sciences last week suggests such interstellar objects could serve as "seeds" for exoplanet growth around young stars.

Planetary formation is believed to occur through a process called accretion — which involves small particles in dusty, gas-rich disks around young stars colliding and sticking together, gradually growing to the size of planets. But there's a bit of a blip in the story. Collisions between boulder-size objects should tend to cause them to bounce or shatter rather than merge.

Pfalzner's models show that interstellar objects — bodies ejected from other star systems — could be captured by these planet-forming disks. These objects could "seed" the disks, sweeping past the growth barrier by providing substantial mass onto which more material can accrete.

"Interstellar objects may be able to jump-start planet formation, in particular around higher-mass stars," Pfalzner said in a statement, noting that simulations predict millions of interstellar bodies could be captured per disk.

This discovery might also solve another mystery. Jupiter-like giant gas planets are most commonly found around more massive stars rather than smaller ones. But the protoplanetary disks around these massive stars only last around 2 million years before dispersing — and that's not quite enough time to create gas giants. But the arrival of interstellar objects into a massive star's disk might speed up the process.

"Higher-mass stars are more efficient in capturing interstellar objects in their disks," said Pfalzner. "Therefore, interstellar-object-seeded planet formation should be more efficient around these stars, providing a fast way to form giant planets. And, their fast formation is exactly what we have observed."

This summer's discovery of 3I/ATLAS — only the third confirmed interstellar object ever observed passing through our solar system, after 1I/'Oumuamua in 2017 and 2I/Borisov in 201— adds credence to this theory. Its detection suggests such objects may be far more common than previously thought, increasing the plausibility that young stars frequently acquire these alien building blocks.

Astronomers have discovered the secret of a strange star system that has baffled them for years, finding it contains a dead star about to erupt after overfeeding on a stellar companion. The supernova explosion of this cosmic cannibal could be as bright as the moon, making it visible with the naked eye over Earth even in broad daylight.

The system in question is the double star V Sagittae located around 10,000 light-years from Earth, containing a white dwarf stellar remnant and its victim companion star, which orbit each other roughly twice every Earth day. The new research and the revelation of this white dwarf's imminent catastrophic fate answer questions about V Sagittae that have lingered for 123 years!

"V Sagittae is no ordinary star system - it's the brightest of its kind and has baffled experts since it was first discovered in 1902," team member and University of Southampton researcher Phil Charles said in a statement. "Our study shows that this extreme brightness is down to the white dwarf sucking the life out of its companion star, using the accreted matter to turn it into a blazing inferno.

"It's a process so intense that it's going thermonuclear on the white dwarf's surface, shining like a beacon in the night sky."

Final fate of a cosmic cannibal

White dwarfs represent the final stage of stars with masses around that of the sun, occurring when they run out of fuel for nuclear fusion. Indeed, our star will end its life as a cooling white dwarf when it runs out of hydrogen in around 5 billion to 6 billion years.

While this smoldering cosmic ember state represents the end for single stars going out with a whimper rather than a bang, white dwarfs that have a stellar companion can get a second lease on life and a more conclusive and explosive end. This happens when its dense stellar corpse is close enough to its companion star to allow its gravity to begin stripping away the partner's stellar material.

This material can't fall straight to the white dwarf because it has angular momentum, or spin. That means it forms a swirling, flattened cloud of matter around the white dwarf called an accretion disk, which gradually dumps matter to its surface.

This situation continues, and the stolen stellar material piles up on the surface of the white dwarf until it pushes this stellar remnant past the so-called Chandrasekhar limit of 1.4 solar masses. This is the mass limit that a stellar remnant has to exceed to trigger a supernova. The result is a Type Ia supernova that usually completely destroys the greedy white dwarf star.

However, this team found something very different and extraordinary happening with the stellar material being stolen by the white dwarf in V Sagittae.

The team uncovered the violent nature of V Sagittae using the Very Large Telescope (VLT), comprised of four individual telescopes located almost 9,000 feet (2,636 meters) on Cerro Paranal in the Atacama Desert of northern Chile.

This investigation revealed that there is a giant halo of gas comprised of material stolen from the companion star wrapped around both the cannibal white dwarf and its stellar victim. This is the result of the incredible amount of energy being generated in the system by the white dwarf as it strips material from its companion star.

This vast system-wide gas halo indicates that the white dwarf is snatching way more matter than it can handle. It also implies that this situation isn't going to continue for long, though when the end will come for this white dwarf isn't quite certain.

"The white dwarf cannot consume all the mass being transferred from its hot star twin, so it creates this bright cosmic ring," team member Pasi Hakala from the University of Turku said. "The speed at which this doomed stellar system is lurching wildly, likely due to the extreme brightness, is a frantic sign of its imminent, violent end."

"The matter accumulating on the white dwarf is likely to produce a nova outburst in the coming years, during which V Sagittae would become visible with the naked eye," Pablo Rodríguez-Gil from Spain’s Instituto de Astrofisica de Canarias said. "But when the two stars finally smash into each other and explode, this would be a supernova explosion so bright it'll be visible from Earth even in the daytime."

The team's research was published on Thursday (Sept. 11) in the journal Monthly Notices of the Royal Astronomical Society.

Some are scorched giants hugging their suns, others are icy wanderers drifting in the dark. And then there are the tantalizing few that might resemble Earth, raising the ultimate question: could life exist out there?

From the groundbreaking Kepler mission to the latest data from the James Webb Space Telescope, you'll dive into the techniques astronomers use to detect these elusive worlds and decode their secrets.

The universe is teeming with planets waiting to be discovered, and this quiz is your chance to explore them. Will you prove yourself a true exoplanet explorer — or get lost in the interstellar shuffle?

Try it out below and see how well you score!

Every once in a while, you may look up towards the sun and see strange bright lights on either side of it. Or perhaps you’ll be sitting in an aircraft, looking out the window at its shadow and see a circle of light, like a halo below (known as glories). Or, if you’re really adventurous, maybe you’ll even be out on a midnight walk with a full moon lighting your way, and see what appears to be a rainbow encircling the moon.

These are all beautiful examples of atmospheric optical phenomena. And a new paper has suggested they may appear in alien skies too.

These celestial wonders can tell us a lot about the state of the atmosphere at home on Earth as well as on other planets. Rainbows, for instance, the most well-known of these phenomena, can only form when light passes through spherical liquid droplets, like our normal rain on Earth. Therefore, there must be spherical liquid droplets in the atmosphere where the rainbows are observed.

Most planet atmospheres have some kind of crystalline aerosols (clouds of tiny particles) in them, from sodium chloride in Io (one of Jupiter's moons), to carbon dioxide crystals in Mars. On Earth, these are generally ice crystals, often found in clouds as snowflakes. The orientation of these crystals, and how they change the light, dictates the type of optical phenomena you can see.

Sun dogs are another of these phenomena, where bright lights appear on either side of the Sun, sometimes even splitting white light into the colors of the rainbow. They form because of the light being bent by horizontally oriented hexagonal ice crystals high up in the atmosphere. If you want the best chance of seeing these, you should try to be at the same latitudes as Europe or Argentina during wintertime. Look for high altitude wispy clouds that are in front of the Sun, and you might get lucky.

Horizontal ice crystals can also create light pillars in extremely cold conditions, which look like colored beams of light trailing to clouds over head. Vertical crystals form parhelic circles – a circle of light at the same height as the Sun. And crystals aligned with the electric fields above thunderstorms create crown flashes.

The new paper proposes that, from what we know of our own atmosphere, we can presume that similar optical phenomena happen on planets outside of our solar system (called exoplanets). It’s just a matter of spotting them and finding out why they occur.

Previous studies have shown that on many exoplanets the crystalline aerosols in their atmospheres are moved around and oriented in a multitude of different ways, much like on Earth.

Magnetic fields swirl around the planet, as they do on Earth, pushing and pulling along field lines. On Earth, this can be seen as the northern lights phenomena. Radiation pressure from a planet's parent star pushes the crystals using the power of light, much like how the wind pushes boats. And the wind, often much faster than anywhere on Earth, speeds around the exoplanet, rushing from the hot, star-facing side of the exoplanet to the colder space-facing side as the planet spins.

A special type of exoplanet, hot Jupiters (so named because they’re huge, gassy and very hot) generally have incredibly fast winds (up to 18,000km/h) and high densities of crystalline aerosols, much like an incredibly fast-moving sandstorm.

This means that the main way that the crystals are oriented is through the superfast winds spinning around the planet. Imagine a fleet of boats all randomly turned around in a patch of ocean, then a massive gust of wind comes, turning them all so that they’re facing the same direction.

The researchers on the new paper previously used the James Webb Space Telescope (JWST) to find evidence for tiny quartz crystals in the high altitude clouds of a hot Jupiter 1,300 light years away from Earth (WASP-17 b). These crystals have an elongated shape, like boats, so are more likely to be oriented with the wind. This led them to think about what optical properties could be seen with the wind-aligned crystals.

The optical phenomena that come from the crystals being oriented the same way cannot be seen by normal cameras. But scientists can use instruments such as those on the JWST to observe these effects.

We have already gained valuable information about faraway atmospheres from looking at their optical phenomena using the JWST. For example on Venus, rainbows and glories have been used by scientists to decipher the mysteries of Venus' extreme heats and yellow color.

A similar technique of observing glories has been used to detect the presence of long-lasting clouds on the exoplanet WASP-76b. The new knowledge of these clouds gives us insight into the exoplanet's atmosphere. Now we know that there can be conditions for a stable temperature, which surprised scientists as half of the planet is hot enough to melt iron.

We can also guess what optical effects might occur on planets where we know what the atmosphere is made of. For example, in the high atmospheres of Jupiter and Saturn, where a special type of ammonia crystals are concentrated, we would expect to observe four separate sun dogs. Alas, on Earth, we can only ever see two at a time due to the shape of our atmospheric ice crystals.

Who knows what other wondrous phenomena we may see on other worlds. Who's to say whether there couldn't be a planet surrounded by continual rainbows? There is much more to learn about so many exoplanets. Optical phenomena such as sun dogs can tell us huge amounts about their atmospheres, which could help us in the search for habitable planets in the future.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Water ice molecules are among the most common in the cosmos and influence the interior and exterior of many planetary bodies in our solar system. Glaciers shape parts of Earth's surface, and dwarf planet Pluto, along with moons such as Europa, Ganymede, Titan, and Enceladus, have whole landscapes made up of ice alone, including boulders, mountains, and even volcanoes.

Under high-pressure or very low temperature conditions, ice forms different crystal structures than those that occur naturally on Earth. Identifying and measuring those structures on worlds such as Ganymede would provide unique data on the interiors of these celestial bodies, in the same way studying mantle rocks pushed to the surface on Earth reveals our planet’s deep geology.

In the lab, researchers can bombard ice with X-rays or neutrons to understand its structure. But such instruments aren’t practical to fly on spacecraft.

Now, new experiments conducted by Christina Tonauer and her colleagues at Universität Innsbruck in Austria show how to distinguish between ice structures using infrared spectroscopy. The analyses, published in Physical Review Letters earlier this summer, can be done using observations from NASA's James Webb Space Telescope (JWST) or the European Space Agency's JUICE (Jupiter Icy Moons Explorer) mission currently en route to Jupiter.

"The ices that we prepare in the lab only occur naturally in space," said Tonauer, whose work combines her field of physical chemistry with her love for planets. "I'm also really interested in astronomy, and this is what hooked me to water ice."

During Tonauer's Ph.D. work in the early 2020s, JWST was still to be launched, but it was clear the infrared observatory would open avenues for studying the ice-covered moons of the outer solar system. When she and her collaborators delved into the literature, they realized that a lot of spectroscopic work on ice—research that largely predated the leaps in understanding gained from the Voyager and Cassini missions—considered infrared (IR) wavelengths longer than those JWST could measure.

It seemed fruitful to Tonauer and her colleagues to study the shorter-wavelength IR spectrum (near-IR) emitted by ice on these distant worlds.

Ice maker, ice maker, make me some ice

As of 2025, 21 different phases of ice have been identified in laboratory experiments, although only one form exists under normal conditions on Earth. That form is called ice I_h (pronounced “ice one aitch”), where "h" refers to the hexagonal pattern the molecule's oxygen atoms take when viewed from one direction.

The conditions that allow researchers to study other ice phases in the lab exist naturally on other planets and moons, however, and scientists have concluded the phases might exist there.

Ganymede and other worlds in the outer solar system likely have something akin to mantle dynamics, for example, but with ice instead of silicate minerals.

Ganymede's mantle could be 800 kilometers thick and consist of several forms of ice that are known only from laboratory experiments on Earth. Tonauer and her collaborators selected ice V and ice XIII for their study, because they form under the high pressures and low temperatures present inside Ganymede and other moons. These phases have the same arrangement of oxygen atoms, but different orientations of hydrogen atoms: In ice V, hydrogen is jumbled around, whereas hydrogen in ice XIII is structured.

Making these types of ice in the lab requires cooling liquid water with liquid nitrogen under about 5,000 atmospheres (500 megapascals) of pressure. As long as the samples are kept cold after forming, Tonauer noted, they don't require high pressure to remain stable because the atoms move so slowly.

However, that slow motion still stretches the bonds between molecules, a vibration that produces IR signals. Using spectroscopy to interpret the emissions, Tonauer and her colleagues discovered that these signals are different for ice V and ice XIII. That difference provided the first experimental demonstration of using IR to distinguish hydrogen configurations within different phases of ice. It also highlighted a way to identify them remotely.

The researchers used a JWST simulator to show that a few hours of observation would be enough to distinguish between these ice phases on Ganymede.

A peek at deep ice

The stability of these ice phases is key to understanding their potential presence on the surface of Ganymede: The phases require high pressure to form, but if brought to the lower-pressure surface, they can maintain their exotic crystal structure indefinitely. In that way, the presence of ice V or XIII would provide details about the icy mantle that would otherwise be inaccessible.

Past and present missions to the Jovian system have clearly indicated that Ganymede's interior contains a liquid water ocean sandwiched between ice layers, but the ices' crystalline structures, as well as how the layers move and evolve, have not been verified by empirical data. According to models of icy moon interiors, the high-pressure environment should produce ice V, which phenomena such as the tidal force from Jupiter might bring to the surface.

These new infrared spectroscopy analyses show how to distinguish between ice I_h, ice V, and ice XIII—not to mention amorphous ice, which lacks a clear crystal structure—without having to return samples to Earth for laboratory analysis (a prohibitively expensive proposition). The method could provide an observational way to verify or refute models of interior ice dynamics, sharpen our picture of Ganymede's internal structure, and help us understand how different flavors of ice behave and interact with each other in a natural environment.

"We can now potentially detect subtle structural differences on icy moons without needing a lander or sample return," said Danna Qasim, a laboratory astrophysicist at the Southwest Research Institute in Texas who was not involved with the new study.

Qasim pointed out that if the grains of these ices are small and jumbled together, it might be difficult to extract their IR signature. As other recent research has shown, amorphous ice in space likely contains chunks of crystalline ice joined together at odd angles, which also might make identification more difficult.

However, the new method seems promising and could well answer vital questions about the internal structure of icy moons.

"We invest billions of dollars in these spectacular space missions," Qasim said. "If we want to truly understand what the data is telling us about these enigmatic beautiful worlds, it is absolutely necessary to have laboratory experiments like the ones performed here."

The planet in question is TRAPPIST-1e, an Earth-sized rocky exoplanet that's located around 40 light-years away from our planet.

TRAPPIST-1e is the fourth planet in orbit around a red dwarf star called TRAPPIST-1. It sits well within the "habitable zone" or Goldilocks zone, the region of space around a star that is neither too hot nor too cold to allow liquid water to exist on the surface of a planet.

However, just existing in the habitable zone of a star isn't sufficient to guarantee the existence of liquid-water oceans or indeed the conditions needed to support life. After all, Earth, Mars, and Venus are all in our solar system's habitable zone, but only one of these planets has water oceans and supports life today (as far as we know). One of the key differences is the atmosphere of our planet, and that is what astronomers are searching for around TRAPPIST-1e.

"TRAPPIST-1e has long been considered one of the best habitable zone planets to search for an atmosphere," study team member Ryan MacDonald, a researcher at the University of St. Andrews in Scotland, said in a statement. "But when our observations came down in 2023, we quickly realized that the system’s red dwarf star was contaminating our data in ways that made the search for an atmosphere extremely challenging."

The JWST data indicate several possible scenarios for TRAPPIST-1e and its potential atmosphere. That makes this research a significant step forward in the search for life beyond the solar system.

To examine the potential atmosphere of TRAPPIST-1e, the team had to wait until it crossed or "transited" the face of its parent star. This reveals details of the chemical composition of a planet's atmosphere because chemicals absorb light at characteristic wavelengths. That means when starlight passes through a planetary atmosphere, the chemicals in that atmosphere leave their characteristic "fingerprints" in the spectrum.

This isn't as straightforward as it may initially sound. Astronomers have to account for factors like starspots across the face of the red dwarf star. So the team has spent the last year carefully removing contamination from the TRAPPIST-1e data to hone in on the planet's atmosphere, or lack thereof.

"We are seeing two possible explanations," MacDonald said. "The most exciting possibility is that TRAPPIST-1e could have a so-called secondary atmosphere containing heavy gases like nitrogen. But our initial observations cannot yet rule out a bare rock with no atmosphere."

The indeterminate nature of the team's results means that JWST is far from finished with TRAPPIST-1e. The researchers hope to perform a deeper search for the planet's atmosphere, with each subsequent transit potentially presenting a clearer picture of its atmospheric contents.

"In the coming years, we will go from four JWST observations of TRAPPIST-1e to nearly 20," MacDonald concluded. "We finally have the telescope and tools to search for habitable conditions in other star systems, which makes today one of the most exciting times for astronomy."

The team's research was published as two papers on Monday (Sept. 8) in The Astrophysical Journal Letters

The protoplanetary disk has an odd chemical composition. It features a surprisingly high concentration of carbon dioxide in the region in which rocky planets like Earth are expected to form and is also unexpectedly low in water content.

The protoplanetary disk investigated by JWST surrounds the infant star XUE 10, which is located around 5,550 light-years from Earth in the vast star-forming region known as NGC 6357. The new discovery was made by the eXtreme Ultraviolet Environments (XUE) collaboration, a research team that focuses on how intense fields of radiation impact the chemistry of protoplanetary disks.

"Unlike most nearby planet-forming disks, where water vapor dominates the inner regions, this disk is surprisingly rich in carbon dioxide," XUE collaboration team member Jenny Frediani, of Stockholm University in Sweden, said in a statement.

"In fact, water is so scarce in this system that it’s barely detectable — a dramatic contrast to what we typically observe," Frediani added. "This challenges current models of disk chemistry and evolution, since the high carbon dioxide levels relative to water cannot be easily explained by standard disk evolution processes."

Strange chemistry

Stars form when overdense patches clump together in vast clouds of gas and dust, eventually gathering enough mass to undergo gravitational collapse. What remains of the material that birthed this still-growing protostar swirls around it, flattening out and eventually forming a protoplanetary disk in which planets can be born.

Scientists currently theorize that planet formation occurs when "pebbles" rich in water ice drift from the colder outer regions of a protoplanetary disk to its warmer inner regions. These higher temperatures cause solid ice to transform directly into gas, a process known as sublimation.

This usually also results in telescopes like JWST spotting strong signals from water vapor in protoplanetary disks. The disk around XUE 10, however, showed strong carbon dioxide signals.

"Such a high abundance of carbon dioxide in the planet-forming zone is unexpected," said XUE Collaboration member and Stockholm University researcher Arjan Bik. "It points to the possibility that intense ultraviolet radiation — either from the host star or neighboring massive stars — is reshaping the chemistry of the disk."

This wasn't the only surprise that JWST delivered to the team with regard to XUE 10 and its protoplanetary disk. Data from the disk revealed molecules of carbon dioxide, enriched with the carbon isotopes carbon-13 and the oxygen isotopes oxygen-17 and oxygen-18.

The presence of these isotopes could help explain why certain unusual isotopes are left in fragments of the early solar system in the formation of meteorites and comets.

The research demonstrates JWST's impressive ability to detect chemical fingerprints in distant protoplanetary disks during crucial eras of planet formation.

"It reveals how extreme radiation environments — common in massive star-forming regions — can alter the building blocks of planets," said team leader Maria-Claudia Ramirez-Tannus from the Max Planck Institute for Astronomy in Germany. "Since most stars and likely most planets form in such regions, understanding these effects is essential for grasping the diversity of planetary atmospheres and their habitability potential."

The team's research was published on Friday (Aug. 29) in the journal Astronomy & Astrophysics.

WISPIT 2b is estimated to be a gas giant around the size of Jupiter and around just 5 million years old. If this seems ancient, remember our solar system is around 4.6 billion years old. The extrasolar planet, or "exoplanet," is carving a channel in the planet-forming disk of gas and dust, or "protoplanetary disk," around its young parent star WISPIT 2 like a cosmic Pac-Man as it gathers material.

The exoplanet is the first confirmed detection of a planet in a multi-ringed protoplanetary disk, a disk that contains multiple gaps and channels, almost akin to a vinyl record.

Imaged using the Very Large Telescope (VLT) located in the Atacama Desert in Chile, WISPIT 2b is also just the second young planet confirmed around a star that is essentially analogous to a young sun.

This makes the study of WISPIT 2b and its home protoplanetary disk, which is as wide as around 380 times the distance between Earth and the sun, the ideal laboratory to study interactions between planets and disks and the subsequent evolution of such systems.

"Discovering this planet was an amazing experience - we were incredibly lucky," team leader and Leiden University researcher Richelle van Capelleveen said in a statement. "WISPIT 2, a young version of our sun, is located in a little-studied group of young stars, and we did not expect to find such a spectacular system. This system will likely be a benchmark for years to come.”

The team captured an infrared image of the planet sitting in a gap in the disk as they conducted an investigation designed to discover if gas giants on wide orbits are more common around young or old stars. This was possible because the infant planet is still hot and glowing following its formation.

"We used these really short snapshot observations of many young stars - only a few minutes per object - to determine if we could see a little dot of light next to them that is caused by a planet," said Christian Ginski, lecturer at the School of Natural Sciences, University of Galway. "However, in the case of this star, we instead detected a completely unexpected and exceptionally beautiful multi-ringed dust disk.

“When we saw this multi-ringed disk for the first time, we knew we had to try and see if we could detect a planet within it, so we quickly asked for follow-up observations."

A separate crew of researchers from the University of Arizona imaged WISPIT 2b in optical light. These observations revealed that WISPIT 2b is still gathering matter.

"Capturing an image of these forming planets has proven extremely challenging, and it gives us a real chance to understand why the many thousands of older exoplanet systems out there look so diverse and so different from our own solar system," Ginski added. "I think many of our colleagues who study planet formation will take a close look at this system in the years to come."

Ginski added that the team was fortunate to have these incredible young researchers on the case of WISPIT 2b, adding that this will be the first of many breakthroughs to come from the next generation of astrophysicists.

"The planet is a remarkable discovery. I could hardly believe it was a real detection when Dr. Ginski first showed me the image," team member and University of Galway MSc student Jake Byrne said. "It's a big one - that's sure to spark discussion within the research community and advance our understanding of planet formation."

The team's research was published across two papers published on Tuesday (Aug. 26) in The Astrophysical Journal Letters.

The StarryStarryProcess builds upon the transit method that has been employed by NASA's TESS (Transiting Exoplanet Survey Satellite) and now-retired Kepler space telescope missions to detect exoplanets. It could be employed by astronomers to assess data from these missions and from NASA's forthcoming Pandora exoplanet-observing satellite.

"Many of the models researchers use to analyze data from exoplanets, or worlds beyond our solar system, assume that stars are uniformly bright disks," study team leader Sabina Sagynbayeva, of Stony Brook University in New York, said in a statement. "But we know just by looking at our own sun that stars are more complicated than that. Modeling complexity can be difficult, but our approach gives astronomers an idea of how many spots a star might have, where they are located and how bright or dark they are."

What do transits tell us?

TESS and Kepler have used the transit method to great effect to discover planets beyond the solar system. In fact, the majority of the over 5,000 worlds in the exoplanet catalog were discovered via the tiny dips in starlight they cause as they cross the face of their parent star.

Tracking how a star's light changes as a planet moves across its face from our position here on Earth helps build a light curve. Brightness falls slightly as the planet moves in front of the star, with minimum brightness achieved when the exoplanet is fully in front of the star. The brightness then steadily increases as the planet moves past the star, bringing the transit to a close.

In addition to helping discover planets, measuring transits can help determine the distance between a planet and its star, as well as the planet's size and rough surface temperature. Additionally, because chemicals absorb light at characteristic wavelengths, as starlight passes through the atmosphere of a planet, a process called spectroscopy can be used to determine the chemical composition of that atmosphere.

However, astronomers often find that light curves aren't as straightforward as they appear. In addition to the drops caused by planetary transits, scientists have spotted dips that are smaller and more complicated. The prevailing theory is that these are the result of "starspots" akin to the sunspots that punctuate the surface of our star, the sun.

The number of sunspots, which are cool and dark patches on the sun, varies across its 11-year solar cycle, with the maximum number of sunspots corresponding with maximum solar activity. They can often be used to predict solar activity and how the solar cycle is progressing.

Therefore, secondary dips in light curves can be used to determine how active the star is, which direction it is tilted, and the angle of the transiting planet's orbit. The StarryStarryProcess takes this to the next level, revealing even more about these characteristics.

"Knowing more about the star in turn helps us learn even more about the planet, like a feedback loop," team member Brett Morris, a senior software engineer at the Space Telescope Science Institute in Baltimore, explained in the same statement.

"For example, at cool enough temperatures, stars can have water vapor in their atmospheres," Morris added. "If we want to look for water in the atmospheres of planets around those stars — a key indicator of habitability — we'd better be very sure that we’re not confusing the two."

To test the StarryStarryProcess, the team looked at the transits a planet called TOI 3884 b makes of its parent star, located around 141 light-years away. The planet is believed to be a gas giant, around five times the size of our planet but with 32 times its mass. TOI 3884 b was discovered in 2022 by TESS.

Using the StarryStarryProcess, the team determined that the parent star of TOI 3884 b has groups of starspots concentrated at its north pole, which is tilted toward Earth. This also means that TOI 3884 b crosses the poles of its parent star from our perspective as it makes its transits.

At the moment, the StarryStarryProcess can only be used in visible light, meaning it can't be applied to exoplanet observations made by the James Webb Space Telescope (JWST). However, the Pandora satellite, which is expected to launch later this year, will make its observations in multiple wavelengths of light, meaning that scientists can make use of this new model again once it starts collecting data.

"The TESS satellite has discovered thousands of planets since it launched in 2018. While Pandora will study about 20 worlds, it will advance our ability to pick out which signals come from stars and which come from planets," Allison Youngblood, TESS project scientist at NASA’s Goddard Space Flight Center in Maryland, said in the statement. "The more we understand the individual parts of a planetary system, the better we understand the whole — and our own."

The team's research was published on Monday (Aug. 25) in The Astrophysical Journal.

In this new model, superheavy dark matter particles could be trapped by exoplanets, losing energy and drifting toward that world's core. Once there, these superheavy dark matter particles accumulate until they collapse, forming a black hole. This black hole then ravenously eats its way out of its host planet.

This new dark matter/black hole theory doesn't work with all recipes of black holes, however. For instance, if dark matter particles meet and annihilate each other as some models suggest (as happens when electrons meet their antiparticles, positrons), then it wouldn't be possible for them to gather in quantities needed to collapse and birth a black hole.

Dark matter is troubling to scientists because, despite the fact that it accounts for 85% of the "stuff" in the universe, we have no idea what it is. The fact that dark matter doesn't interact with light means it can't be made up the electrons, protons, and neutrons that form the atoms that compose everything we see around us: the universe's ordinary matter — stars, planets, moons, living things, etc.. This lack of interaction with electromagnetic radiation also makes dark matter effectively invisible. This puzzle has led to scientists to suggest all types of different particles that might possibly account for dark matter, many of which have different properties.

But there's another caveat to the dark matter recipe needed for this process to occur. The constituent particles would have to have very large masses. This rules out one of the most highly favored dark matter candidate particles, the axion, a hypothetical particle with a very small mass.

"If the dark matter particles are heavy enough and don't annihilate, they may eventually collapse into a tiny black hole," University of California, Riverside researcher Mehrdad Phoroutan Mehr said in a statement. "If the dark matter particles are heavy enough and don’t annihilate, they may eventually collapse into a tiny black hole."

How are dark matter black holes born?

Currently, the lightest black holes we are aware of are so-called stellar mass black holes. These are thought to have masses between around 3 and 100 times the mass of the sun. The logic behind this is sound, as these black holes are born when massive stars run out of nuclear fuel at the end of their lives. As a supernova explosion ejects the outer layers of these stars, their stellar cores collapse.

That means the mass range of stellar mass black holes is set by the masses of the progenitor stars that created them. Furthermore, the lower mass is set by the fact that stars with less than 1.4 times the mass of the sun (a value known as the Chandrasekhar limit) can't go supernova, so can't birth a black hole or a neutron star. Instead, these stars leave behind a white dwarf.

There's another mass limit to consider, too. The Tolman–Oppenheimer–Volkoff (TOV) limit divides stellar cores that create black holes and those that birth neutron stars. Though less well defined than the Chandrasekhar limit, the TOV limit suggests that after ejecting most of its matter, a stellar core needs to have at least 2.2 to 2.9 times the mass of the sun to form a black hole.

This limit is uncertain, as currently the lightest black hole we have detected and confirmed is around 3.8 times the mass of the sun, while the heaviest neutron star ever detected weighs in at 2.4 solar masses.

These planet-eating black holes would be much more diminutive than even the lightest stellar mass black hole if they adopt the mass of the planet they devour. The team proposes that this process could occur within planets with masses the same as Jupiter, which has around 0.001 times the mass of the sun.

"In gaseous exoplanets of various sizes, temperatures, and densities, black holes could form on observable timescales, potentially even generating multiple black holes in a single exoplanet's lifetime," Phoroutan-Mehr said. "These results show how exoplanet surveys could be used to hunt for superheavy dark matter particles, especially in regions hypothesized to be rich in dark matter like our Milky Way's galactic center."

Of course, other than watching a planet devoured from the inside out, the creation pathway of stellar mass black holes and the TOV limit means that detecting a black hole with a mass less than the sun could support the team's theory.

"Discovering a black hole with the mass of a planet would be a major breakthrough," Phoroutan-Mehr said. "If astronomers were to discover a population of planet-sized black holes, it could offer strong evidence in favor of the superheavy non-annihilating dark matter model."

This new theory, combined with the growing catalog of exoplanets, with over 5,000 worlds beyond the solar system, means these planets can now be added to the celestial bodies that have been suggested as dark matter probes.

An example of that is the suggestion that certain dark matter candidates could become trapped in neutron stars, gathering and gradually annihilating each other thus heating these stellar remnants.

"So, if we were to observe an old and cold neutron star, it could rule out certain properties of dark matter, since dark matter is theoretically expected to heat them up," Phoroutan-Mehr said.

Dark matter trapping within exoplanets could also cause heating within these worlds or it could cause them to emit high-energy radiation.

"Today's instruments aren't sensitive enough to detect these signals. Future telescopes and space missions may be able to pick them up," Phoroutan-Mehr concluded. "As we continue to collect more data and examine individual planets in more detail, exoplanets may offer crucial insights into the nature of dark matter."

The team's research was published on Wednesday (Aug. 20) in the journal Physical Review D.

However, that still leaves four other planets in orbit around TRAPPIST-1 that could be habitable, with at least two or three of them in what is regarded as the "habitable zone" where temperatures would be suitable for liquid water to exist —- assuming an Earth-like atmosphere that can retain heat.

Previously, the James Webb Space Telescope (JWST) had failed to find evidence for an atmosphere around the two innermost planets in the TRAPPIST-1 system, world TRAPPIST-1b and TRAPPIST-1c. Now, we can add the next planet out, TRAPPIST-1d, to the list.

"Ultimately, we want to know if something like the environment we enjoy on Earth can exist elsewhere, and under what conditions," Caroline Piaulet-Ghorayeb of the University of Chicago and the Trottier Institute for Research on Exoplanets (IREx) at Université de Montréal, said in a statement. "At this point, we can rule out TRAPPIST-1d from a list of potential Earth twins or cousins."

All seven planets of the TRAPPIST-1 system are seen transiting, or passing in front of, their star. Although not even the JWST can see the silhouette of the transiting planet, it can detect where the star's light has been absorbed by molecules in the planet's atmosphere during the transit. This is called transmission spectroscopy.

Yet, despite using the JWST's sensitive Near-Infrared Spectrometer, or NIRSpec, astronomers led by Piaulet-Ghorayeb found no evidence for water, methane or carbon dioxide, all of which are common in Earth's atmosphere and which act as natural greenhouse gases to retain heat and keep a planet warm enough for liquid water.

"There are a few potential reasons why we don't detect an atmosphere around TRAPPIST-1d," said Piaulet-Ghorayeb. "It could have an extremely thin atmosphere that is difficult to detect, somewhat like Mars. Alternatively, it could have very thick, high-altitude clouds that are blocking our detection of specific atmospheric signatures — something more like Venus. Or, it could be barren rock, with no atmosphere at all."

The problem that the TRAPPIST-1 planets collectively face is their star. Red dwarfs, small and cool, seem at first glance to be unthreatening, but in reality they are tumultuous with frequent violent outbursts of radiation. These repeated flares can strip an atmosphere from a world a piece at a time. It is quite possible that this is the fate that has befallen TRAPPIST-1b, c and d. In particular, planet d seems like a real blow to our hopes of finding a world with an Earth-like atmosphere around TRAPPIST-1 because it resides on the inner edge of the system's habitable zone. That said, so does Venus in our solar system, and a Venus-like planet is still on the table. And there are four other planets still to go.

"All hope is not lost for atmospheres around the TRAPPIST-1 planets," said Piaulet-Ghorayeb. "While we didn't find a big, bold atmospheric signature for planet d, there is still potential for the outer planets to be holding onto a lot of water and other atmospheric components."

Planets e and f are definitely in the star's nominal habitable zone, g is at the outer edge like Mars is in our solar system, while planet h is beyond the habitable zone and will be almost certainly too cold to support an Earth-like atmosphere.

However, probing whether any of these outer planets has an atmosphere is more difficult. Their greater distance from their star means any spectral signature is weaker, perhaps too weak even for the JWST to detect.

But even if all the worlds around TRAPPIST-1, which is 40 light-years away, prove to be a bust, there are many more fish in the sea. Red dwarf stars are by far the most common type of star, making up about three-quarters of all stars in the Milky Way galaxy, and there are numerous other interesting planets around other red dwarfs, such as Teegarden's Star b, LHS 1140b and even Proxima Centauri b, even though the latter does not transit. And the search continues for rocky planets in the habitable zone of more sun-like stars — a search that the European Space Agency's PLATO mission, currently set to launch in December 2026, will accelerate.

The latest news regarding the search for an atmosphere around TRAPPIST-1d was published on Aug. 13 in The Astrophysical Journal.

Using JWST's Mid-Infrared Instrument (MIRI), the team imaged Alpha Centauri with a coronagraphic mask to remove the glare from the stars, allowing them to see much fainter objects like planets. That revealed a potential orbiting world some 10,000 times fainter than Alpha Centauri A.

While the planet candidate is in Alpha Centauri A's habitable zone — the range of distances from a star where it's possible for liquid water to exist on a world's surface — it is a gas giant and thus wouldn't be able to support life as we know it. Still, the potential planet is an exciting discovery.

For starters, it's sure to generate interest from sci-fi fans — after all, the "Avatar" film series' fictional moon Pandora circles a gas giant that orbits Alpha Centauri A.

But there's much intrigue within the realm of science, too. At a distance of just two astronomical units from its host star (twice the distance between Earth and the sun), the planet candidate, if confirmed, would be the closest to its host star ever imaged. It would also be the first planet imaged around a star that matches the sun in both age and temperature.

"With this system being so close to us, any exoplanets found would offer our best opportunity to collect data on planetary systems other than our own," Charles Beichman, the executive director of the NASA Exoplanet Science Institute at the California Institute of Technology (Caltech) and a senior scientist at NASA's Jet Propulsion Laboratory in Southern California, said in a statement.

The Alpha Centauri system hosts two confirmed exoplanets, both of them around the red dwarf star Proxima Centauri. There's still a long road ahead before the candidate Alpha Centauri A gas giant can join the list.

Subsequent JWST observations did not reveal additional evidence of the planet, though computer simulations suggest the planet might just have been too close to Alpha Centauri A to be imaged.

The team hopes that further observations by both JWST and the upcoming Nancy Grace Roman Space Telescope, scheduled to launch in May 2027, might provide the proof required to confirm the planet.

That would certainly give scientists much to study in the years to come. "[The planet's] very existence in a system of two closely separated stars would challenge our understanding of how planets form, survive, and evolve in chaotic environments," said Aniket Sanghi, a Caltech graduate student who co-led the research with Beichman.

The scientists report the new results in two papers that have been accepted for publication in The Astrophysical Journal Letters.

These fiery worlds share a similar density to Earth but orbit so close to their host stars that their scorching daytime temperatures melt the very rocks they're made of, creating possible oceans of magma that cover their surface.

While lava worlds represent an exciting new frontier in exoplanet science, much remains unknown about their dynamics, interiors and evolutionary paths. "Lava planets are in such extreme orbital configurations that our knowledge of rocky planets in the solar system does not directly apply, leaving scientists uncertain about what to expect when observing lava planets," Charles-Édouard Boukaré at York University in Toronto, co-author of a new study about lava worlds, said in a statement.

Given that lava planets have been identified as key targets for observation with NASA's James Webb Space Telescope (JWST), with five different programs already planned to study them, Boukaré and colleagues developed a conceptual framework — a "blueprint" of sorts — that outlines possible key characteristics, such as chemistry, surface conditions and other distinctive traits, to guide astronomers in identifying and analyzing these planets.

Using a numerical model, the researchers predicted the long-term evolution of lava planets over billions of years, from their formation to the point where they achieve a "thermal steady state." By combining insights from geophysical fluid mechanics, exoplanetary atmospheres, and mineralogy, the study reveals how the intense internal dynamics and shifting compositions of these exotic worlds likely unfolds over time.

But the model's foundation was based on findings made closer to home. "These processes, though greatly amplified in lava planets, are fundamentally the same as those that shape rocky planets in our own solar system," Boukaré said.

Interestingly, while lava planets are predicted to start out mostly molten right after they form, much like magma oceans on young planets in our solar system, they solidify nearly as quickly as their solar system counterparts despite being heated on their star-facing side. (Lava worlds are "tidally locked" to their host stars, with one hemisphere always in darkness and the other always in the very bright light.)

What makes lava planets unique is that, unlike rocky planets in our solar system, they maintain a shallow magma ocean on their sun-facing side for billions of years, even as their interiors slowly cool. Along the edges of this magma ocean, crystals continuously form from the molten rock, causing a constant separation of different chemical components between the solid crystals and the remaining liquid magma, according to the new study.

This ongoing process shapes and changes the planet over time, so the silicate atmosphere of an older lava planet reflects a chemically changed magma ocean — not the planet's original makeup. This means it's possible to tell the age of a lava planet by studying its atmosphere.

"Unlike the relatively low-density short-period exoplanet 55 Cancri e, bona fide lava planets are expected to have lost all their volatiles to space, but their 2,000–3,000 K[elvin; 1,727 to 2,727 degrees Celsius] daysides support an atmosphere of vaporized silicate rocks, which may be observable with the James Webb Space Telescope (JWST)," the researchers wrote in their paper, which was published in the journal Nature on July 29.

Additionally, young lava planets have relatively warm nightside temperatures around 1,500 K (1,227 degrees C), caused by heat from internal convection. As they age, without additional heat sources, their nightside cools significantly. A planet's current thermal state reflects its entire thermochemical history, making mantle temperature a key to understanding planetary evolution.

Measuring nightside temperatures is now possible with the JWST, providing insights into a planet's interior. Future telescopes like the Extremely Large Telescope, which is currently under construction in Chile, may also analyze silicate atmospheres, helping to reveal the complex interactions between a planet's atmosphere, molten surface and interior minerals.

What started as a "highly exploratory effort with few initial expectations" has grown into an exciting new frontier in exoplanet science, providing clear guidelines to help astronomers identify and study this new class of planets.

These predictions have played a key role in the team securing 100 hours of valuable observation time on JWST.

"We really hope we can observe and distinguish old lava planets from young lava planets. If we can do this, it would mark an important step toward moving beyond the traditional snapshot view of exoplanets," concluded Boukaré.

While signs of life on the world have failed to conclusively present themselves to the James Webb Space Telescope (JWST), the powerful space telescope has discovered that this planet is so rich in liquid water that it could be an ocean, or "Hycean" world.

"This has certainly increased the chances of habitability on K2-18 b" Nikku Madhusudhan, the University of Cambridge scientist behind the original K2-18b discovery as well as the new study, told Space.com. "This is a very important development and further increases the chance of a Hycean environment in K2-18 b. It confirms K2-18 b to be our best chance to study a potential habitable environment beyond the solar system at the present time."

The story regarding the habitability of K2-18 b began back in April 2025, when Madhusudhan and fellow researchers from the University of Cambridge announced they had found what they called the "strongest evidence yet" of life beyond the solar system around this distant super-Earth (it's around nine times as massive as our planet).

The evidence came from the tentative detection of molecules that, when found in the atmosphere of Earth, are typically the result of biological processes of living things. The pressure was then on to confirm these potential biosignatures: dimethyl sulfide and dimethyl disulfide.

The team set about this by observing four separate instances of K2-18 b crossing, or "transiting," the face of its parent red dwarf star, located about 124 light-years away, during its roughly 33-Earth-day orbit. Because chemicals absorb and emit light at characteristic wavelengths, when light from a parent star passes through a planet's atmosphere, the molecules in that atmosphere leave their telltale fingerprints in the spectrum of starlight.

"With four additional transit observations using JWST, we have measured the spectrum of K2-18 b’s atmosphere with unprecedented precision," Renyu Hu, the new study's team leader and a NASA Jet Propulsion Lab scientist, told Space.com. "The spectrum allowed us to conclusively detect both methane and carbon dioxide in the planet's atmosphere and to constrain their abundances. This information points to a planet with a water-rich interior."

Hu explained that the team searched for signals of dimethyl sulfide and other organic sulfur molecules in the spectrum using several independent models, but did not find conclusive evidence for their presence.

"This was not necessarily disappointing," Hu continued. "We're excited about establishing the planet’s water-rich nature."

Is K2-18 b a ocean world?

Saying it's now confirmed that K2-18 b is water-rich, Hu explained that the next step is to discover if the planet possesses a global liquid water ocean.

Ironically, one of the most positive signs of such an ocean is the fact that the atmosphere of this super-Earth appears to lack water vapor.

"The spectrum we obtained does not show signs of water vapor. If the atmosphere truly lacks water, this suggests that water has been depleted — most likely through condensation," Hu said. "On Earth, this process is known as the 'cold trap,' and geoscientists consider it essential for retaining water over billions of years by preventing it from escaping to space.

"Observing a similar process on an exoplanet would be very exciting. Rigorously confirming the absence of water can by itself be a scientifically important goal for future observations," Hu said.

However, Hu cautioned that the spectrum detected by the JWST could also be explained by an alternative model in which the atmosphere actually contains abundant water vapor.

Establishing whether K2-18 b and other similar temperate, sub-Neptune-sized planets possess liquid water oceans, Hu says, will also require detecting the presence of a broader set of atmospheric gases beyond methane and carbon dioxide. It would also require an absence of molecules like ammonia, carbon monoxide and sulfur dioxide, which, as of yet, have indeed not been detected in the atmosphere of K2-18 b

"This conclusion is based on theoretical work by my group and several others," Hu added. "With the new observations providing valuable context, we've summarized these insights into a roadmap to help guide future observations and studies."

Meanwhile, the search for the biosignatures, dimethyl sulfide and dimethyl disulfide, is far from done; while not hitting the significance level required for a confirmation, this research did provide a stronger signal from these molecules than were provided by previous examinations.

"The evidence for dimethyl sulfide in the present work is significantly higher than what we had with our previous observations in the same near-infrared wavelength range," Madhusudhan said. "However, this evidence is still not high enough to claim a conclusive detection.

"We also need to be able to distinguish dimethyl sulfide from other possible contributors, such as methyl mercaptan, which is also a biosignature on Earth."

It looks certain that K2-18 b will continue to hold the interest of astronomers for some time.

"It is great that we are able to infer tentative signs of potential biosignatures with current JWST observations, but significantly more time is needed for conclusive detections. A key question is whether the atmosphere contains one or more biosignatures," Madhusudhan said. "At the same time, extensive theoretical and experimental efforts are needed to robustly identify biological and non-biological pathways for candidate biosignature molecules."

One thing the team is sure of, though, is the progress made thus far in the study of K2-18 b wouldn't have been possible without the JWST. And, the $10 billion space telescope is set to play a key role in the future investigation of this super-Earth.

"Our observations and analyses add to the growing list of exciting discoveries that highlight the truly transformative science enabled by JWST," Hu concluded. "While we found its Near-Infrared Spectrograph [NIRSpec] particularly well suited to address the goals of our study, other JWST instruments or observational modes could provide complementary and highly valuable information to further enhance our understanding of this planet."

The team's research is available as a preprint on the paper repository arXiv.

These rogue planetary systems would also be much smaller than the solar system, possessing just a fraction of the total mass of our cosmic neighborhood.

The finding came about when a team of researchers used the James Webb Space Telescope (JWST) to examine young, isolated objects in space that are believed to have between five and 10 times the mass of Jupiter. These objects, unlike the planets of the solar system, were also unbound to a star and therefore free-floating in the universe.

These bodies could have formed in the same way stars form from collapsing clouds of gas and dust, hence their isolated nature. Yet, unlike stars, the free-floating planetary bodies would have failed to gather enough mass to trigger nuclear fusion in their cores, the process that defines what a main-sequence star is. That makes them akin to so-called "failed star" brown dwarfs, but with lower masses. Brown dwarfs have masses that range from 13 to 80 times the mass of Jupiter.

Alternatively, some free-floating planets are believed to have formed around stars from classic, swirling donuts of gas and dust called protoplanetary disks. They would've then been ejected from their home systems by gravitational interactions with their sibling planets and even with passing stars.

"These discoveries show that the building blocks for forming planets can be found even around objects that are barely larger than Jupiter and drifting alone in space," Belinda Damian, lead author of the research and a scientist at the University of St. Andrews, said in a statement. "This means that the formation of planetary systems is not exclusive to stars but might also work around lonely starless worlds."

The right stuff to spot planetary rogues

Believed to be the lowest mass bodies that can form from isolated clouds of gas and dust, free-floating planets are difficult to spot and study due to the fact that they emit very little light of their own. But the electromagnetic radiation free-floating planets do emit is mostly infrared light, the wavelength of light that the JWST is sensitive to.

As such, the study team honed in on eight young, free-floating planets with the powerful infrared space telescope.

The observations conducted between August and October of 2024 revealed detailed characteristics of the bodies, indicating that they have masses around that of Jupiter. Six of the free-floating planets exhibited an extended infrared emission generated by warm dust immediately around them. That indicated surrounding disks of gas and dust, the kind of structures that gather around infant stars to spawn planets.

Even more exciting than this was the detection of grains of silicates in these disks. That is an early indication of dust collecting together and crystallizing — and that, in turn, is the first stage in the formation of "rocky," or terrestrial, planets like Earth.

Traces of silicates have been seen around stars and even brown dwarfs before, but this is the first time these fingerprints have been found around much smaller free-floating planets. The team's finding backs prior research, which suggested that protoplanetary disks forming around free-floating planets could survive for several million years.

That is a period of time long enough to allow planets to form.

"Taken together, these studies show that objects with masses comparable to those of giant planets have the potential to form their own miniature planetary systems," team leader and University of St. Andrews astronomer Aleks Scholz said. "Those systems could be like the solar system, just scaled down by a factor of 100 or more in mass and size."

With the plausibility of these starless mini-planetary systems established and early fingerprints of their formation detected, the next step for astronomers will be to detect such a system.

"Whether or not such systems actually exist remains to be shown," Scholz said.

The team's research was published on Wednesday (July 30) in The Astronomical Journal.

Rogue, or "free-floating," planets are worlds that don't orbit a star. They earn their rogue status when they are ejected from their home systems due to interactions with their sibling planets or via gravitational upheaval caused by passing stars.

The most successful way of detecting an extrasolar planet, or exoplanet, in general is waiting until it crosses, or "transits," the face of its parent star. Being cosmic orphans without a stellar parent, however, rogue planets can't be detected in this way. Fortunately, a phenomenon first predicted by Einstein in 1915 offers a way to spot these rogue worlds.

"Free-floating planets, unlike most known exoplanets, don't orbit any star. They drift alone through the galaxy, in complete darkness, with no sun to illuminate them. That makes them impossible to detect using traditional planet-detection techniques, which rely on light from a host star," Przemek Mroz, study team member and a professor at the University of Warsaw, told Space.com. "To find these elusive objects, we use a technique called gravitational microlensing."

How Einstein became a rogue planet hunter

Einstein's 1915 theory of gravity, general relativity, suggests that objects with mass cause the very fabric of space to "warp." The bigger the mass, the greater the warp and thus the stronger the gravity that arises from the warp.

Gravitational lensing arises when light from a background source passes by the warp. Its path gets curved. This can amplify that background source, an effect that astronomers use with Hubble and the James Webb Space Telescope (JWST) to study extremely distant galaxies that would usually be too faint to see.

"This phenomenon occurs when a massive object, the lens, passes in front of a distant star (the source), magnifying the star's light due to the lens's gravity," Mroz explained. "The beauty of microlensing is that it works even if the lensing object emits no light at all.

"During microlensing events, the source star gets temporarily magnified. We can estimate the mass of the lensing object by measuring the duration and other properties of the event."

Mroz added that when microlensing events are generated by passing rogue planets, they are usually very short, lasting less than a day.

The particular microlensing event the team studied to reveal this new rogue world is designated OGLE-2023-BLG-0524 and was observed by Hubble on May 22, 2023, remaining buried in data from the space telescope.

"It was discovered in the direction of the Galactic bulge by the Optical Gravitational Lensing Experiment [OGLE] survey, and independently observed by the Korea Microlensing Telescope Network [KMTNet]," Mroz said. "The Einstein timescale of the event was just eight hours, making it one of the shortest microlensing events on record."

Based on the microlensing event’s properties, Mroz and colleagues were able to estimate that the lensing body object could be either a Neptune-mass planet located in the Milky Way's galactic disk, around 15,000 light-years away. Alternatively, the rogue world could be a larger but more distant Saturn-mass object in the Milky Way's galactic bulge, roughly 23,000 light-years away.

"Both scenarios are consistent with the microlensing signal we observed," Mroz said.

Hunting for planets in Hubble's archives

One of the most important tasks that faced the team upon the discovery of the microlensing event OGLE-2023-BLG-0524 was determining that this was indeed caused by a rogue planet, and not by a planet associated with a star but on a wide orbit far from its stellar parent.

They reasoned that if the planet had a nearby host star, within 10 times the distance between Earth and the sun (10 AU), they would have likely seen a second, longer-lasting microlensing signal from the star. The researchers saw no such signature, so they could rule out that the planet had a close stellar companion.

However, if the planet orbits a star at a much wider separation, greater than 10 AU, the odds of detecting the host star are much lower.

"This means we can’t fully rule out the wide-orbit scenario, but here's where it gets interesting," Mroz said. "Because the lens and the background star are slowly moving relative to each other, they will eventually separate in the sky.

"If we detect light from the lensing object at that point, we'll know it’s not completely free-floating."

Unfortunately, Mroz explained that the distance between the planet and the background star means their relative motion appears incredibly small, about 5 milliarcseconds per year.

"It will take at least a decade before we can hope to resolve them with current instruments, such as the Hubble Space Telescope or large ground-based telescopes," Mroz said.

Hubble was particularly useful in this rogue planet hunt because the region of the sky that hosts the microlensing event was observed by the long-serving space telescope way back in 1997. That's over 25 years before the microlensing event.

"That gave us a unique opportunity to test whether there might be a star associated with the lens," Mroz said. "According to our model, by 1997, the lens and source should have been separated by 0.13 arcseconds. That's tiny, but within Hubble's capabilities. If the lens were a bright star, we would have seen it in those old images. But we didn't."

The absence of detectable light at the expected lens position told the team that any potential host star would have to be very faint.

"Depending on the stellar population model we use, that rules out around 25% to 48% of possible companion stars," Mroz said. "That pushes us further toward the conclusion that this may truly be a free-floating planet."

Mroz explained that OGLE-2023-BLG-0524 was discovered by team member Mateusz Kapusta by chance while the team was following up on microlensing events.

"This discovery was partly serendipity!" Mroz said. "It was a lucky break, but we believe there are many more such opportunities hidden in the data.

"Microlensing events occur all the time in dense stellar fields, and many of those fields have been observed by Hubble in the past. That means there could be more interesting events waiting to be discovered in the Hubble data."

The team's research is available as a preprint on the paper repository arXiv.

Located about 35 light-years from Earth, L 98-59 is a cool, dim red dwarf star already known to host a compact system of small, rocky planets. The latest discovery, led by researchers at the Université de Montréal's Trottier Institute for Research on Exoplanets, confirms the presence of L 98-59 f, a super-Earth with a minimum mass 2.8 times that of our planet.

The newly discovered exoplanet follows an almost perfectly circular 23-Earth-day orbit around its star. The world receives roughly the same amount of stellar energy as Earth, placing it in the star's habitable zone — a range of distances where liquid water could exist under suitable atmospheric conditions, according to a statement from the university.

"Finding a temperate planet in such a compact system makes this discovery particularly exciting," Charles Cadieux, a postdoctoral researcher at the university and lead author of the study, said in the statement. "It highlights the remarkable diversity of exoplanetary systems and strengthens the case for studying potentially habitable worlds around low-mass stars."

L 98-59 f was discovered by reanalyzing data from the European Southern Observatory's (ESO) HARPS (High Accuracy Radial velocity Planet Searcher) and ESPRESSO (Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations) spectrographs. Since the exoplanet doesn't transit, or pass in front of, its host star from our perspective, astronomers spotted it by tracking subtle shifts in the star's motion that are caused by the planet's gravitational pull.

By combining the spectrograph data with observations from NASA's TESS (Transiting Exoplanet Survey Satellite) and James Webb Space Telescope (JWST) — and using advanced techniques to filter out stellar noise — researchers were able to determine the size, mass and key properties of all five planets.

The study shows that L 98-59 b, the innermost planet, is just 84% the size of Earth and half its mass, making it one of the smallest exoplanets measured. Tidal forces may drive volcanic activity on the system's two innermost planets, while the third's unusually low density suggests it could be a water-rich world unlike any in our solar system. This diversity offers a rare opportunity to investigate the formation and evolution of planetary systems beyond our own, team members said.

"These new results paint the most complete picture we've ever had of the fascinating L 98-59 system," Cadieux said. "It's a powerful demonstration of what we can achieve by combining data from space telescopes and high-precision instruments on Earth, and it gives us key targets for future atmospheric studies with the James Webb Space Telescope."

Because L 98-59 is small and nearby, its planets are especially well-suited for follow-up atmospheric studies. If L 98-59 f has an atmosphere, telescopes like JWST may be able to detect water vapor, carbon dioxide — or even biosignatures.

The new study was published July 12 in the journal Earth and Planetary Astrophysics.

Astronomers have seen what appears to be a forming planet carving out a complex pattern in a disk of gas and dust around a young star. The discovery of this spiral architect could help us better understand how planetary systems like the solar system came to be.

The infant extrasolar planet, or "exoplanet," is creating a spiral arm pattern in the planet-forming protoplanetary disk of the 10 million-year-old star HD 135344B, also known as SAO 206462, located in the Scorpius OB2-3 star-forming region. If 10 million years old doesn't seem particularly young, remember the sun is considered middle-aged — and its around 4.6 billion years old.

The discovery of the potential planetary culprit for this swirling spiral pattern was made using the Very Large Telescope (VLT) and its Enhanced Resolution Imager and Spectrograph ERIS) instrument. It may represent the first time astronomers have witnessed a planet actively forming within a protoplanetary disk.

"We will never witness the formation of Earth, but here, around a young star 440 light-years away, we may be watching a planet come into existence in real time," Francesco Maio, study team leader and a researcher at the University of Florence, said in a statement.

Maio and colleagues estimate this budding planet is around twice as large as Jupiter. It orbits HD 135344B at a similar distance to Neptune's orbit around the sun. That's about 30 times the distance between Earth and the sun.

And as this potential planet seems to carve channels into the protoplanetary disk of HD 135344B, it is gathering material to further facilitate its growth.

Baby exoplanet sweeps up stellar leftovers

Stars form from overly dense cool patches in vast clouds of interstellar gas and dust, which collapse under their own gravity. As these stars continue to grow, swirling clouds of gas and dust called protoplanetary disks settle around them. It is within this disk that planets will be born.

Astronomers predict that when this happens, these infant worlds sweep up material to build their own masses, creating intricate structures like rings and channels similar to the grooves in a record, and spirals resembling the spiral arms of the Milky Way. However, catching these exoplanet sculptors has been challenging.

Exemplifying this is the fact that astronomers had previously detected the spiral structure of HD 135344B's protoplanetary disk, using the VLT Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument — but had missed evidence of a planet causing it.

However, ERIS allowed the VLT and its operators to dive deeper into this protoplanetary disk, revealing a prime suspect for its shape: a hidden exoplanet sculptor.

This potential baby planet lurks at the base of one of the disk's spiral arms. That is exactly where scientists have predicted such a spiral-sculpting infant planet should dwell.

"What makes this detection potentially a turning point is that, unlike many previous observations, we are able to directly detect the signal of the protoplanet, which is still highly embedded in the disk,” Maio explained. "This gives us a much higher level of confidence in the planet’s existence, as we’re observing the planet's own light."

The team's research was published on Monday (July 21) in the journal Astronomy & Astrophysics.

Using NASA's Chandra X-ray spacecraft, astronomers have witnessed a distant, Jupiter-size world "shrinking" as its host star bombards it with heavy radiation.

The extrasolar planet, or "exoplanet," is named TOI 1227 b and is a cosmic baby at just 8 million years old (remember, Earth is around 4.5 billion years old). And, incredibly, the world orbits its star at a distance of just 8.2 million miles, a fraction of the distance between the sun and Mercury, with a year that lasts just 28 days. This proximity means the star, named TOI 1227 and located around 330 light-years away, is blasting the planet with powerful X-rays.

This radiation is stripping the exoplanet's atmosphere away; in fact, the atmosphere of TOI 1227 b is likely to be completely gone in around 1 billion years. This will reduce the exoplanet to nothing more than a small, rocky and barren core.

The team behind this research estimates TOI 1227 b will have ultimately lost the equivalent of two Earths' worth of mass by the conclusion of its transformation. As of now, the world has a mass around 17 times that of Earth's.

"It's almost unfathomable to imagine what is happening to this planet," Attila Varga, study team leader and a researcher at the Rochester Institute of Technology (RIT), said in a statement. "The planet's atmosphere simply cannot withstand the high X-ray dose it’s receiving from its star."

While this exoplanet's parent star is less massive than the sun (with about 10% the mass of our star) and is cooler and fainter in optical light, it is actually brighter than our star in X-rays.

"A crucial part of understanding planets outside our solar system is to account for high-energy radiation like X-rays that they're receiving," team member and RIT scientist Joel Kastner said in the statement. "We think this planet is puffed up, or inflated, in large part as a result of the ongoing assault of X-rays from the star."

The team used Chandra to determine just how much X-ray radiation is roasting TOI 1227 b. The researchers then used computer modeling to assess the impact of this radiation on the exoplanet and its atmosphere. This revealed that roughly every two centuries, the world loses the equivalent of Earth's entire atmosphere from its own atmosphere.

"The future for this baby planet doesn't look great," Alexander Binks, a study team member and researcher at Eberhard Karls University of Tübingen, said in the statement. "From here, TOI 1227 b may shrink to about a tenth of its current size and will lose more than 10 percent of its weight."

The researchers estimated the age of TOI 1227 b using estimates of its host star's velocity through space and comparing them with the speed of nearby stellar populations with known ages. The team also compared the surface brightness of TOI 1227 with models of stellar evolution.

TOI 1227 b stands out from other exoplanets aged less than 50 million years because, among the set, it seems to have the longest year and a host star with the lowest mass.

The team's research has been accepted for publication in The Astrophysical Journal and appears as a preprint on the repository site arXiv.

The extrasolar planet or "exoplanet" in question is TOI-2109b, which has five times the mass of Jupiter and is located around 870 light-years from our solar system. The planet orbits so close to its parent star, TOI-2109, that it has a year that lasts just 16 hours.

These characteristics mean that TOI-2109b is classified as an "ultrahot Jupiter," a rare class of planets that account for around 1 in 500 planets in the over 5,000 worlds in the catalog of known exoplanets. But TOI-2109b stands out even among those incredibly hot, star-hugging worlds.

"This is an ultra-hot Jupiter, and orbits much closer to its star than any other hot Jupiter ever discovered," Macquarie University Research Fellow Jaime A. Alvarado-Montes said in a statement."Just to put it into context, Mercury's mass is almost 6,000 times smaller than Jupiter's, but it still takes 88 days to orbit our sun.

"For a huge gas giant such as TOI-2109b to fully orbit in 16 hours, it tells us that this is a planet located super-close to its star."

That makes TOI-2109b the perfect laboratory to study planets' death spirals into their host stars, or more accurately, the phenomenon of orbital decay.

The three deaths of TOI-2109b

Alvarado-Montes and colleagues set about investigating TOI-2109b using archival data from multiple telescopes, including NASA's Transiting Exoplanet Survey Satellite (TESS) and the European Space Agency (ESA) space mission Cheops.

This constituted data regarding the transits of TOI-2109b across the face of its parent star from 2010 to 2024.

"Using all of the data available for this planet, we were able to predict a small change in its orbit," Alvarado-Montes said. "Then we verified it with our theory and with our planet evolution models, and our predictions matched the observations. That's quite exciting."

The matching theoretical estimations and observational evidence suggested that the orbit of TOI-2109b will decay by around 10 seconds over the next three Earth-years. Though this is a tiny change, it proves TOI-2109b is spiraling toward its parent star.

The ultimate fate of TOI-2109b is uncertain, as there are three possible ways that this death spiral could play out.

The first and most dramatic final fate of TOI-2109b would see the ultrahot Jupiter plunge into its parent star. This will occur if the orbital decay of this planet begins to accelerate.

"The star will absorb it and kill it, of course, in the process – completely burn it, and the planet will disappear," Alvarado-Montes said.

This would create a flash of light that is similar to ZTF SLRN-2020, a signal first observed in May 2020 when a gas giant planet plunged into its red giant stellar parent.

The second possible fate of TOI-2109b is slightly less dramatic, but no less catastrophic.

This would happen if the orbital decay of the planet continues unabated and sees the gravity of its parent star generate destructive tidal forces within the planet. These forces would literally rip TOI-2109b apart.

"The gravitational interactions are so strong that the planet starts being distorted," Alvarado-Montes said. "It starts looking more like an elongated doughnut ... the gravity of the planet is no longer able to hold its spherical shape."

There is a third possible fate which would see the planet transformed rather than being destroyed.

In the third possible scenario for TOI-2109b, the intense radiation experienced by the ultrahot Jupiter strips away the planet's gassy outer layers in a process called photoevaporation. This would expose the rocky inner core of TOI-2109b.

"As the planet gets even closer to the star, all of the gas molecules could start being dissociated, and the planet gets smaller and smaller," Alvarado-Montes explained. "And if the planet shrinks quickly enough, then when the planet reaches the position where its Roche limit would have been, it's not going to be five Jupiter masses anymore, but it will be small enough that the Roche limit moves closer to the star, so it could escape destruction."

This could ultimately result in the creation of a rocky "super-Earth" around the size of Uranus or Neptune.

The team will continue to monitor TOI-2109b over the next three to five years, which should reveal the fate that will befall this doomed world.

The investigation of TOI-2109b has implications beyond its own fascinating and fateful situation. It provides astronomers the chance to study how hot Jupiters evolve and what happens when planets migrate toward their host stars.

"This planet and its interesting situation could help us figure out some mysterious astronomical phenomena that so far we really don't have much evidence to explain," Alvarado-Montes concludes. "It could tell us the story of many other solar systems."

The team's research was published on Tuesday (July 15) in The Astrophysical Journal.

That's the theory of a team of researchers who looked at hundreds of extrasolar planets, or exoplanets, observed by NASA's Transiting Exoplanet Survey Satellite (TESS).

TESS hunts exoplanets by catching them as they cross the face of, or "transit," their parent star, which causes a tiny drop in light from that star. The study team discovered that light from stars neighboring the one being transited could "contaminate" TESS' data, making it look like the transiting planet is blocking less light than it actually is. And that would make the planet look smaller than it is.

"We found that hundreds of exoplanets are larger than they appear, and that shifts our understanding of exoplanets on a large scale," University of California, Irvine researcher and team leader Te Han said in a statement. "This means we may have actually found fewer Earth-like planets so far than we thought."

Exoplanets throw shade

Exoplanets are so distant and faint that it is only on rare occasions that astronomers can image them directly.

That means the transit method has become the most successful way of detecting worlds beyond the solar system. It requires the planet and its star to be at the right angle in relation to Earth, and for astronomers to wait for the planet to make two transits to confirm its existence.

The transit method is best at spotting short-period planets orbiting close to their host stars, because they make more frequent transits. The method also favors larger planets, which block more light.

"We’re basically measuring the shadow of the planet," said team member and UC Irvine astronomer Paul Robertson.

The team gathered hundreds of TESS observations of exoplanets, sorting them by the width of the exoplanets in question.

They then used computer modeling and data from the European Space Agency's (ESA) star-tracking mission Gaia to estimate how much light contamination TESS is experiencing during its observations.

"TESS data are contaminated, which Te's custom model corrects better than anyone else in the field," said Robertson. "What we find in this study is that these planets may systematically be larger than we initially thought. It raises the question: Just how common are Earth-sized planets?"

Move over Earth-like worlds: ocean planets could be more common

Because of the biases of the transit method mentioned above, the number of exoplanets detected with TESS having sizes and compositions similar to those of Earth was already low.

"Of the single-planet systems discovered by TESS so far, only three were thought to be similar to Earth in their composition," Han explained. "With this new finding, all of them are actually bigger than we thought."

The likely outcome of this is that those exoplanets are larger ocean planets or "hycean worlds" covered by a large single ocean. Those worlds could also be gas giants smaller than Jupiter, like Neptune and Uranus.

That impacts the search for life because, though hycean worlds are packed with water, they could be lacking other ingredients needed for life to arise.

"This has important implications for our understanding of exoplanets, including, among other things, prioritization for follow-up observations with the James Webb Space Telescope, and the controversial existence of a galactic population of water worlds," Roberston added.

The next step for Han, Roberston, and colleagues is to re-examine planets previously deemed uninhabitable due to their size, to see if they are larger than previously thought.

In the meantime, the research is a reminder to astronomers to be cautious when assessing TESS data.

The team's research was published on Monday (July 14) in the Astrophysical Journal Letters.