Exoplanet Kelt-9b Atmosphere Molecule
Exoplanet KELT-9b, which is currently the hottest known planet, has an atmosphere that can decompose hydrogen molecules. That’s right, this happens every single day during the daytime hours of the planet and the molecules then rejoin at night. This planet boasts 3 times the mass of Jupiter and the surface temperature reaches as high as 4300°C. Read more for a video and additional information.

This decomposition event occurs in the star-facing part of the planet, while the molecules recover in the night, when the temperatures drop before the cycle begins all again during the daytime. KELT-9b is located in the Milky Way galaxy and orbits a star around 670 light-years away.

This kind of planet is so extreme in temperature, it is a bit separate from a lot of other exoplanets. There are some other hot Jupiters and ultra-hot Jupiters that are not quite as hot but still warm enough that this effect should be taking place,” said Megan Mansfield, a graduate student at the University of Chicago and lead author of a new paper revealing these findings.