Astronomers from the University of Arizona, alongside an international research team, have used NASA’s James Webb Space Telescope (JWST) to observe the atmosphere of the exoplanet WASP-107b, revealing groundbreaking findings about its atmospheric asymmetry.
This hot, inflated planet, similar in size to Jupiter but only a tenth of its mass, exhibits significant east-west asymmetry, making it a unique discovery in the study of exoplanets.
The study, led by graduate student Matthew Murphy from the University of Arizona’s Steward Observatory, was published in Nature Astronomy. It marks the first time such asymmetry has been observed in an exoplanet during its transit — when it passes in front of its star — using space-based observation.
WASP-107b is tidally locked, meaning one side of the planet perpetually faces its host star, while the other remains in permanent darkness. This configuration results in dramatic differences in atmospheric conditions between the planet’s day side and night side.
The JWST allowed Murphy’s team to observe these differences using transmission spectroscopy, a technique that analyzes light passing through a planet’s atmosphere to determine its composition, structure, and other characteristics.
“Thanks to the unprecedented precision of the James Webb Space Telescope, we were able to separate the signals from the eastern and western hemispheres of the planet’s atmosphere, providing a clearer picture of its dynamics,” Murphy explained.
The findings have offered new insights into the atmosphere’s gases, cloud formations, and the impact of varying sunlight exposure on each side of the planet.
WASP-107b is particularly unique because of its low density, making its atmosphere more inflated compared to other exoplanets of similar mass. Despite its extreme temperature of 890°F, WASP-107b occupies a middle ground between the planets in our solar system and the hottest exoplanets discovered.
“This discovery has opened new doors,” Murphy said. “Our models didn’t predict such an asymmetry for a planet like this, so we’re already learning new things.”