Gliese 581d

This world, which is about seven times as massive as Earth, orbits a bit farther out than its planetary sibling Gliese 581g.

When 581d was first discovered in 2007, many scientists regarded it as too cold to be potentially habitable. In the years since, however, atmospheric-modeling studies have suggested that the planet may indeed be able to support life as we know it — provided 581d is warmed by a greenhouse effect.

Astronomers have found new evidence of the existence of an Earth-like planet that lies a comparative stone’s throw away from our solar system.

Discovery of the planet known as GJ 581d was heralded in 2007 but new research last year cast doubt on the claims, saying data used to find it was probably just misinterpreted signals from stars.

Astronomers had used a spectrometer to spot the planet, which measures “wobbles” in the wavelength of light emitted by a star caused as a planet orbits it.

GJ 581d was said to be a super-Earth with a mass seven times that of our own planet orbiting a red dwarf star that could also support up to four other planets.