Webb Finds a Lava Planet That Should Have Lost Its Atmosphere — Shielded by Reflective Mineral Clouds

BIRMINGHAM, 27 October 2026 — Astronomers using the James Webb Space Telescope have found that a scorching lava planet some 280 light-years from Earth appears to be wrapped in a reflective layer of clouds that acts like a sunscreen, even though theory suggested such an extreme world should have lost its atmosphere billions of years ago, the University of Birmingham reported on 27 October 2026.

Illustration: A rocky lava planet with a glowing molten surface and bright reflective clouds near its star.

What Happened

An international research team, including University of Birmingham astrophysicist Dr Anjali Piette, published their findings in The Astronomical Journal after using the James Webb Space Telescope to observe a lava planet called TOI-561 b for 37 hours, capturing nearly four complete trips around its star. The team found evidence that the planet has a substantial global atmosphere, albeit one that is not liveable, which appears to reflect a significant amount of incoming starlight.

The key surprise is how much light the planet turns away. Data from the observations indicate that TOI-561 b reflects about three-quarters of the starlight that reaches it, a level of reflectivity comparable to Venus, according to reports of the study. Earlier temperature measurements had puzzled researchers because the planet's dayside was considerably cooler than predicted for a dark rocky world orbiting so close to its star.

Two explanations were on the table for the missing heat: it could be carried around to the nightside by the atmosphere, or reflected away before the planet ever absorbed it. The new analysis suggests both may be happening, but heat transport alone cannot explain the relatively cool dayside. Reflective silicate clouds, potentially composed of silicon dioxide and magnesium silicate, may form above the dayside and function as a reflective barrier, while the atmosphere also distributes heat from the illuminated side toward the perpetually dark hemisphere.

Dr Piette said the discovery challenges current theories. "We would expect a heavily irradiated rocky planet like TOI-561 b to have lost its atmosphere billions of years ago," she said, according to the University of Birmingham. "Instead, the evidence suggests it still has a significant atmosphere today. This raises major questions such as whether the planet started with an unusually large supply of gases or if the ocean of molten rock covering its surface acts as a planet-wide volcano that is constantly feeding its atmosphere."

Background

TOI-561 b is a rocky super-Earth about 280 light-years from Earth, roughly 1.4 times Earth's width, according to reports of the study. It orbits its star in about 10.7 hours, so close that its surface is thought to be a global ocean of magma, and it receives thousands of times more starlight than Earth gets. It is tidally locked, meaning one side permanently faces its star while the other sits in endless night.

That combination made it a test case for how rocky planets keep or lose their atmospheres. A small, intensely heated world should, on standard theory, have had its gases stripped away long ago by stellar radiation, leaving a bare rock. TOI-561 b was therefore previously considered too hot to retain a substantial atmosphere, and its dayside was expected to be a dark, blazing surface.

Illustration: The James Webb Space Telescope with its golden mirrors floating in deep space.

Webb changed what astronomers could measure. By tracking the planet's infrared brightness across nearly four full orbits, the team could compare the dayside and nightside and work out how heat moves around the planet. A bare rock would show a very hot dayside and a very cold nightside, with little in between. What Webb saw instead was a dayside cooler than expected and a nightside warm enough to require an atmosphere moving heat around the globe.

The study, led by researchers including Lisa Dang at the University of Waterloo with Dr Piette among the team, builds on earlier evidence that TOI-561 b possesses a substantial atmosphere. The new work sharpens the picture: carrying heat away from the dayside cannot account for all of its apparent cooling, so a reflective component is needed, and mineral clouds are the leading explanation.

What the atmosphere is actually made of remains an open question. It could be a dense blanket of carbon dioxide, like a much hotter version of Venus, or it could be rich in sulphur dioxide, a gas released from a volcanic moon like Io, according to the University of Birmingham. Webb has not directly identified the clouds' mineral ingredients, so the silicate-cloud explanation remains the best-supported model rather than a direct detection.

Why It Matters

The finding matters because it rewrites expectations for rocky planets around other stars. If a lava world as extreme as TOI-561 b can hold on to a thick, reflective atmosphere, then atmospheres may be far more resilient on rocky exoplanets than models assumed. That has knock-on effects for how astronomers interpret observations of other rocky worlds, including those closer to habitable conditions, where the presence or absence of an atmosphere is the difference between a barren rock and a world that could conceivably support liquid water.

It also shows Webb's power as a weather station for distant worlds. The telescope cannot photograph surface features on a planet 280 light-years away, but by measuring brightness changes over an orbit it can reveal clouds, heat transport and reflectivity. Techniques proven on an extreme world like TOI-561 b can then be applied to cooler, smaller planets where the stakes for habitability are higher.

The result also opens a new puzzle about where the atmosphere comes from. Either TOI-561 b began with an unusually large supply of gases that has survived billions of years of intense heating, or its magma ocean is continuously replenishing the atmosphere like a planet-wide volcano. Distinguishing between those histories will require further observations, and the answer will feed into models of how all rocky planets, including Earth in its early molten phase, evolved.

For the public, the "sunscreen" image captures something real about planetary science: clouds made not of water but of vaporised rock, condensing high above a sea of lava, bouncing starlight back into space. It is a reminder that weather exists far beyond Earth, in forms stranger than anything in our own solar system.

What Happens Next

Astronomers will now try to pin down what TOI-561 b's atmosphere is made of. Further Webb observations, and eventually observations with future telescopes, could look for the chemical fingerprints of carbon dioxide, sulphur dioxide or silicate minerals directly, testing whether the cloud explanation holds up and which gases dominate.

Illustration: Astronomers studying exoplanet data on large screens in an observatory control room.

Researchers will also compare TOI-561 b with other lava worlds and hot rocky planets to see whether reflective mineral clouds are common or exceptional. If similar reflectivity shows up elsewhere, models of atmospheric loss on rocky planets will need broad revision. If TOI-561 b turns out to be unusual, the question becomes what makes it special: its starting composition, its volcanic activity, or something else entirely.

The study also sets up a longer programme of work on magma-ocean worlds, a class of planet with no analogue in the present-day solar system. Understanding them helps astronomers read the early history of rocky planets, since Earth itself is thought to have had a magma ocean in its infancy. A planet that still has one today, wrapped in rock-vapour clouds, is a living laboratory for that violent chapter of planetary history.

TOI-561 b itself will never be a place for life as we know it: a surface of molten rock under intense stellar heat is far outside any range where biology could survive. Its value is not as a second Earth, but as a challenge to theory, and as proof that even the most extreme planets can still surprise the telescopes pointed at them.

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Frequently Asked Questions

What is TOI-561 b?

TOI-561 b is a rocky super-Earth about 280 light-years from Earth, roughly 1.4 times Earth's width, whose surface is thought to be a global ocean of magma. It orbits its star in about 10.7 hours.

What did Webb discover about it?

Webb observations over 37 hours, covering nearly four orbits, suggest TOI-561 b has a substantial global atmosphere that reflects about three-quarters of the starlight reaching it, leaving its dayside cooler than expected for a bare rock.

What are the reflective clouds made of?

Researchers propose silicate mineral clouds, potentially composed of silicon dioxide and magnesium silicate, forming above the dayside. Webb has not directly identified their ingredients, so this remains the leading model rather than a confirmed detection.

Could anything live on TOI-561 b?

No. Its surface of molten rock under intense stellar heat is far outside any range where life as we know it could survive. Its scientific value lies in what it reveals about how rocky planets keep or lose atmospheres.

What is still unknown about the planet?

What its atmosphere is made of remains open: it could be a dense carbon dioxide blanket like a much hotter Venus, or rich in sulphur dioxide like gas from a volcanic moon such as Io. Further observations are needed to decide.

Sources

• University of Birmingham, "Shiny lava planet challenges astronomers' expectations," 27 October 2026.
• SciTechDaily, "This Alien Planet Should Have Lost Its Atmosphere Billions of Years Ago," 28 October 2026.
• The Brighter Side of News, "Venus or volcanic Io? Lava planet TOI-561 b's reflective mineral clouds puzzle astronomers," 27 October 2026.
• Piette et al., The Astronomical Journal, 2026 (TOI-561 b study, as reported by the University of Birmingham).
• Martin Cid Magazine, "A lava planet that should be bare rock reflects 74% of its starlight, Webb finds," October 2026 (orbit period, size and irradiation figures, as reported).