A new study shows that an exoplanet contains strange sand clouds high in the atmosphere. While the James Webb Space Telescope (JWST or Webb) may spend a lot of time observing the farthest reaches of the early universe, where galaxies were just beginning to form, it also spends a lot of time looking at objects much closer to home. – such as the atmospheres of outer planets in our galactic neighbors.

A team of European astronomers used JWST observations to describe in detail the composition of the atmosphere of a nearby “puffy” exoplanet called WASP-107b. Researchers have discovered clouds of water vapor, sulfur dioxide and even silicate sand in the exoplanet’s dynamic atmosphere. The new research may also have implications for our understanding of the chemistry of distant planets.

Exoplanet WASP-107b is one of the least dense planets known to astronomers and is sometimes compared to a comet. The planet is about the same size as Jupiter but has only 12% of its mass. WASP-107b is about 200 light-years from Earth and takes only six days to orbit its host star, which is slightly cooler and less massive than our Sun.

The planet’s low density, or softness, allowed astronomers to probe the planet’s atmosphere 50 times deeper than observations made for denser planets like Jupiter.

The first discovery of sulfur dioxide (the smell that occurs when you light a match) surprised astronomers. This is because the host star, WASP-107b, emits high-energy photons of light at a relatively small rate due to the planet being smaller and cooler. But the planet’s low density means these photons can penetrate deep into WASP-107b’s atmosphere, triggering chemical reactions that form sulfur dioxide.

In addition to sulfur dioxide, astronomers also noted the presence of high-altitude clouds composed of small silicate particles (mainly very fine-grained sand).

Researchers suggest that sand clouds consist solely of sand droplets, similar to water vapor and clouds on Earth. As sand raindrops condense and fall, they collide with very hot layers inside the planet, where they turn into silicate vapor and return to the surface, where they condense again and form clouds again.

“JWST will revolutionize the characterization of exoplanets by providing unprecedented information at extraordinary speed,” lead author Len Dechin, of the Catholic University of Leuven in Belgium, said in a press release.

“The discovery of sand, water and sulfur dioxide clouds on this puffy exoplanet… is a major milestone. “It transforms our understanding of planetary formation and evolution, shedding new light on our own solar system,” he added.

The observations were made with the JWST Mid-Infrared Instrument (MIRI), a spectrograph that can probe planetary atmospheres in the mid-infrared or thermal range. The paper was published in the journal Nature on Wednesday, November 15.