Newslink: Rocky-Planet-Like Atmospheres Are Possible on 3 TRAPPIST-1 Planets

A new study of several planets in the habitable zone of the star TRAPPIST-1, which is home to seven known Earth-size planets, suggests that the planets' atmospheres look similar to those found on rocky planets such as Venus or Mars.

https://www.space.com/39613-trappist-1-planet-atmospheres-lack-hydrogen.html