The Webb telescope reveals a 3D atmosphere map of a hot planet that’s hot enough to break down water molecules

American astronomers used the James Webb Space Telescope (JWST) to draw a 3D atmospheric map of WASP-18b, an extremely hot exoplanet, for the first time. This study, jointly led by the University of Maryland and Cornell University, found that there are extreme temperature differences in the planet's atmosphere, and some areas are hot enough to decompose water molecules.

Scientists used the James Webb Space Telescope (JWST) to create a three-dimensional map of the atmosphere of WASP-18b, revealing the scorching areas where water molecules are broken down. (An artist’s impression of the exoplanet WASP-18b.) Image credit: NASA/GSFC

WASP-18b is about 400 light-years away from the Earth. It is a type of "super-hot Jupiter" with a mass ten times that of Jupiter. It only takes 23 hours to orbit its main star. Scientists used "spectral eclipse mapping" technology to obtain a three-dimensional temperature distribution covering latitude, longitude and altitude by analyzing the light absorbed at different wavelengths. This result significantly surpasses previous two-dimensional mapping levels and will help study the atmospheric structure of more exoplanets in the future.

Research shows that WASP-18b is tidally locked, with one side always facing the host star. A hot, high-temperature area appears on the front of the planet, with temperatures as high as about 5,000 degrees Fahrenheit (about 2,760 degrees Celsius), where water vapor is decomposed at a rapid rate; while the edge areas are relatively cold, allowing water molecules to exist. This confirms theoretical predictions that temperature changes in different regions of a single planet's atmosphere can lead to differences in the survival of molecules.

Scientists say that this new mapping method will help observe and analyze many known "hot Jupiters" and rocky exoplanets similar to the Earth. It is expected to further reveal their thermal and chemical structures. In the future, it can also be used to analyze the surface temperature components of planets without atmospheres.

Compiled from /ScitechDaily