Astronomers have discovered a super-Earth in the "habitable zone" - meaning it could support liquid water and a stable atmosphere - around a nearby star, HD 40307. Previously discovered planets around it are called "hot super-Earths" because they orbit too close to the star to support life.
HD 40307 is a dwarf star that is somewhat smaller and less luminous than the Sun that is about 42 light years away (12.88 parsecs). Besides the super-Earths, it has three other low-mass planets orbiting it.
An international team of researchers used newly developed software that is able to process the signals more thoroughly and thereby reveal the presence of the three additional planets.
The most interesting of the new planets is in the outermost orbit from the star, a distance that is similar to the distance between the Earth and our Sun. Its mass is at least seven times the mass of the Earth. The planet is likely rotating on its axis while in orbit, possibly creating a day/night cycle and an Earth-like environment.
The star HD 40307 is a quiet old dwarf star, making it possible the planet could sustain an Earth-like climate.
sources:
Carnegie Institution for Science