Hubble sees new atmosphere forming on a rocky exoplanet

[Roberto]

For the first time, scientists using the NASA/ESA Hubble Space Telescope have found evidence of volcanic activity reforming the atmosphere on a rocky planet around a distant star. The planet, GJ 1132 b, has a similar density, size, and age to Earth.

https://www.cam.ac.uk/research/news/hubble-sees-new-atmosphere-forming-on-a-rocky-exoplanet

The planet GJ 1132 b appears to have begun life as a gaseous world with a thick blanket of atmosphere. Starting out at several times the radius of Earth, this 'sub-Neptune' quickly lost its primordial hydrogen and helium atmosphere, which was stripped away by the intense radiation from its hot, young star. In a short period of time, it was reduced to a bare core about the size of Earth.

To the surprise of astronomers, new observations from Hubble have uncovered a secondary atmosphere that has replaced the planet's first atmosphere. It is rich in hydrogen, hydrogen cyanide, methane and ammonia, and also has a hydrocarbon haze. Astronomers theorise that hydrogen from the original atmosphere was absorbed into the planet's molten magma mantle and is now being slowly released by volcanism to form a new atmosphere. This second atmosphere, which continues to leak away into space, is continually being replenished from the reservoir of hydrogen in the mantle's magma.