Atmosphere found on Earth-like planet in habitable zone

For the first time, astronomers have detected an atmosphere around a rocky, Earth-sized planet located in the habitable zone of its star, a major milestone in the search for life beyond our solar system. The planet, known as GJ 1132 b, orbits a red dwarf star about 39 light-years away in the constellation Vela. This discovery marks the first confirmed atmosphere on a planet of this size and type in a region where liquid water could exist on the surface.

The finding, published in the Astronomical Journal, was made by a team led by researchers at the Center for Astrophysics | Harvard & Smithsonian. Using observations from the Hubble Space Telescope, they detected signatures of hydrogen and helium in the planet's atmosphere, along with possible traces of water vapor. The planet itself is about 1.4 times the size of Earth and completes an orbit every 1.6 days, placing it well within the habitable zone of its dim, cool star.

This discovery matters because it demonstrates that Earth-like planets in habitable zones can retain atmospheres, a key requirement for potential habitability. Previous searches for atmospheres on such worlds had been unsuccessful, often finding bare rocks or tenuous exospheres. GJ 1132 b now becomes a prime target for further study, especially with upcoming telescopes like the James Webb Space Telescope, which could analyze its atmosphere in greater detail.

The planet was originally discovered in 2015 by the MEarth-South project, which searches for small planets around nearby red dwarfs. Since then, it has been a focus of follow-up observations. The detection of its atmosphere was made possible by observing the planet as it passed in front of its star, allowing scientists to measure the starlight filtered through the atmosphere. The team plans to continue observing GJ 1132 b to confirm the presence of water and search for other molecules, such as methane or oxygen, that could indicate biological activity.