Astronomers have detected the strongest evidence yet of an #atmosphere around a rocky #planet beyond our solar system.
Rhe planet TOI-561 b is a rocky world that's about twice Earth's mass but bears little resemblance to our home planet due to its proximity to its host #star.
Although the star is slightly less massive and cooler than our sun, the planet orbits at one fortieth the distance of #Mercury in our own solar system.
On TOI-561 b, a year lasts just 10.56 hours, and one side of the planet is in perpetual daylight.
A planet like this is too small and hot to retain its own atmosphere for long after formation. But observations suggest that it is surrounded by a relatively thick blanket of gas, upending conventional wisdom about ultra-short-period planets.
There is an equilibrium between the #magma ocean and the atmosphere. At the same time that gases are coming out of the planet to feed the atmosphere, the magma ocean is sucking them back into the interior
https://phys.org/news/2025-12-ultra-hot-lava-world-thick.html
Paper by Teske et al. (2025):
https://iopscience.iop.org/article/10.3847/2041-8213/ae0a4c