by In a groundbreaking discovery, a team of European astronomers, led by researchers from the Institute of Astronomy, KU Leuven, has used the James Webb Space Telescope to study the atmosphere of the nearby exoplanet WASP-107b. The observations revealed the presence of water vapor, sulfur dioxide, and even silicate sand clouds in the planet’s fluffy atmosphere. These findings provide crucial insights into the dynamics and chemistry of this unique exoplanet.
The James Webb Space Telescope (JWST) is equipped with the Mid-Infrared Instrument (MIRI), which allows astronomers to conduct pioneering observations of exoplanets. WASP-107b is a gaseous exoplanet that orbits a star slightly cooler and less massive than the Sun. It has a similar mass to Neptune but is much larger in size, resembling Jupiter. The fluffiness of WASP-107b enables astronomers to delve deep into its atmosphere, approximately 50 times deeper than they can explore the atmosphere of a planet like Jupiter in our solar system.
Taking advantage of WASP-107b’s fluffiness, the team of European astronomers discovered water vapor, sulfur dioxide, and silicate clouds in its atmosphere. Notably, they found no traces of methane, a greenhouse gas. The absence of methane suggests a potentially warm interior of the planet and offers insights into the movement of heat energy in its atmosphere. The presence of sulfur dioxide, previously thought to be absent, was a major surprise. The planet’s fluffy nature allows the formation of sulfur dioxide in its atmosphere, despite its host star emitting a relatively low amount of high-energy photons.
Another significant finding is the presence of high-altitude silicate clouds that partially obscure the water vapor and sulfur dioxide. These clouds consist of small silicate particles, similar to sand on Earth. This marks the first time astronomers have definitively identified the chemical composition of clouds on an exoplanet. The discovery of these sand clouds, water vapor, and sulfur dioxide reshapes our understanding of planetary formation and evolution, providing new insights into our own Solar System.
In contrast to Earth’s atmosphere, where water freezes at low temperatures, gaseous planets with temperatures reaching around 1000 degrees Celsius can produce silicate clouds. However, the traditional models predicted that these clouds should be forming at higher temperatures within the atmosphere of WASP-107b. The team discovered that the sand clouds exist at high altitudes because the sand rain droplets evaporate in deeper, hotter layers, and the resulting silicate vapor moves back up to recondense into clouds again. This cyclic process is similar to the water vapor and cloud cycle on Earth, but instead, it involves sand droplets.
The pioneering research on WASP-107b’s atmosphere not only provides insights into this unique exoplanet but also expands our understanding of exoplanetary atmospheres. It represents a significant milestone in exoplanetary exploration, revealing the intricate interplay between chemicals and climatic conditions on distant worlds.
The MIRI instrument used in this study was designed and developed with the contributions of Belgian engineers and scientists, funded by the Belgian federal science policy office BELSPO via the ESA PRODEX program. The extensive testing of the MIRI instrument was conducted at the Institute of Astronomy at KU Leuven, along with other laboratories in the UK and the NASA Goddard and NASA Johnson Space centers.
Dr. Bart Vandenbussche of KU Leuven, an instrument specialist involved in the project, expressed satisfaction in seeing the instrument unravel the atmosphere of WASP-107b. Dr. Jeroen Bouwman of the Max-Planck-Institut für Astronomie in Germany highlighted the years of work invested in building the MIRI instrument and the calibration and analysis tools used in analyzing the observational data acquired with MIRI. With the combination of several independent analyses of the JWST observations, this study brings together the collective effort of researchers across Europe and the United States.
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1. Source: Coherent Market Insights, Public sources, Desk research
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