Upon further investigation, it seems that Gliese 581d may be the only one of the two actually in the habitable zone, and its ...

Illustration of the habitable zone boundaries as obtained by the two ... The middle part of the figure shows the limits of the HZ of Gliese 581 computed with the atmospheric models from Selsis ...

Two years ago the ESO team also found that Gliese 581’s planet “D,” which orbits its star in the “habitable zone,” could have water on the surface of the planet. “[Planet] D could even ...