(CN) — A group of European astronomers got a deeper glimpse into the dynamic atmosphere of a nearby exoplanet unlike any other object in our own solar system, thanks to observations from the James Webb Space Telescope.
Researchers, led by the Institute of Astronomy at KU Leuven in Belgium, presented their investigation of the atmosphere of the Neptune-like exoplanet WASP-107b in a study published Wednesday in the journal Nature.
"JWST is revolutionizing exoplanet characterization, providing unprecedented insights at remarkable speed," said lead author Leen Decin of KU Leuven in a statement. "The discovery of clouds of sand, water, and sulfur dioxide on this fluffy exoplanet by JWST's MIRI instrument is a pivotal milestone. It reshapes our understanding of planetary formation and evolution, shedding new light on our own solar system."
WASP-107b — which orbits a star slightly cooler and smaller than our sun, just over 200 light years away from Earth — was discovered in 2017 and is notable for its fluffy appearance.
It was this fluffiness that allowed astronomers to study the complex chemical composition of the exoplanet’s atmosphere; they looked 50 times deeper into its atmosphere than would be possible for similar but denser gas giants like Jupiter and Neptune.
Using the James Webb’s Mid-Infrared Instrument, or MIRI, developed in part by KU Leuven scientists, researchers identified water vapor and sulfur dioxide in the exoplanet’s atmosphere and, significantly, the absence of the greenhouse gas methane. The lack of methane suggests the planet may have a warm interior and could shed light on the movement of heat energy.
Observations from MIRI shocked astronomers with the presence of sulfur dioxide, which they concluded formed because the exoplanet’s "fluffiness" allowed photons from its sun to reach deep enough into its atmosphere to cause the chemical reaction.
Also notable were the high-altitude clouds made of silicate particles that cover the exoplanet. The researchers note that sand clouds are not unheard of, as silicate particles can freeze on gas planets in high temperatures up to 1832 degrees Fahrenheit (1000 degrees Celsius). They had expected the clouds to form deeper within the atmosphere on WASP-107b, however, as it has a temperature closer to 932 degrees Fahrenheit (500 degrees Celsius).
"The fact that we see these sand clouds high up in the atmosphere must mean that the sand rain droplets evaporate in deeper, very hot layers and the resulting silicate vapor is efficiently moved back up, where they recondense to form silicate clouds once more. This is very similar to the water vapor and cloud cycle on our own Earth but with droplets made of sand,” University of Amsterdam’s Michiel Min, the study's co-author, said.
Though its cloud system may be similar to Earth’s, astronomers say that the cozy-looking exoplanet has no analog to planets of our own solar system. However, the observations help them expand their understanding of the formation of atmospheres and climates of distant exoplanets.
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