A team of European astronomers, led by researchers from the Institute of Astronomy at KU Leuven, utilized the advanced capabilities of the James Webb Space Telescope (JWST) to study the atmosphere of the nearby exoplanet WASP-107b. This groundbreaking research, recently published in Nature, employed observations from the Mid-Infrared Instrument (MIRI) aboard the JWST to delve into the unique characteristics of the exoplanet’s atmosphere.
WASP-107b, located in our cosmic neighborhood, orbits a star slightly cooler and less massive than the Sun. While its mass is similar to Neptune, its substantial size makes it remarkably “fluffy” compared to gas giant planets in our solar system. The fluffiness allows astronomers to penetrate 50 times deeper into its atmosphere than with solar-system giants like Jupiter.
The study unveiled significant components in the atmosphere of WASP-107b, including water vapor, sulfur dioxide (SO2), and silicate sand clouds. Notably absent was methane (CH4), offering insights into the planet’s potentially warm interior and the movement of heat energy within its atmosphere. Surprisingly, sulfur dioxide was detected, challenging previous models that predicted its absence. Climate models now suggest that the fluffiness of WASP-107b enables the formation of sulfur dioxide in its atmosphere, even with its host star emitting a relatively small fraction of high-energy photons due to its cooler nature.
Moreover, the study identified high-altitude clouds obscuring water vapor and sulfur dioxide, marking the first instance where astronomers definitively identified the chemical composition of these clouds. These clouds consist of small silicate particles akin to sand, challenging traditional models that predicted the formation of these clouds at deeper levels within the atmosphere.
The continuous cycle of sublimation and condensation through vertical transport was observed, explaining the enduring presence of sand clouds at high altitudes. The research, funded by the Belgian federal science policy office BELSPO, contributes to understanding WASP-107b and expands our knowledge of exoplanetary atmospheres, marking a significant milestone in exoplanetary exploration.
Dr. Leen Decin of KU Leuven emphasized the pivotal role of JWST, stating, “JWST is revolutionizing exoplanet characterization, providing unprecedented insights at remarkable speed.” This study showcases the intricate interplay of chemicals and climatic conditions on distant exoplanets, advancing our understanding of these exotic worlds.
