Key points:
LHS 1140 b is an Earth‑size planet about 5.6 times the mass of Earth orbiting a small, cool red dwarf star.
The planet lies in the habitable zone, receiving less than half the sunlight Earth receives.
Scientists identified the atmosphere by detecting helium gas leaking into space during a transit observation.
The detection was made by observing a dip in the star’s infrared light at the wavelength where helium absorbs.
Before accounting for the atmosphere, the planet’s estimated surface temperature was roughly –53 °F. Read more, see photos and video here.


