Gliese 581d （格利澤581d） PHI: 0.43

Gliese 581d or Gl 581d is an extrasolar planet orbiting the star Gliese 581 approximately 20 light-years away in the constellation of Libra. It is the third planet discovered in the system and the fifth in order from the star. (From Wikipedia)

Because of its mass, at least 5.6 times that of Earth, the planet is classified as a super-Earth. Originally believed to be outside the habitable zone, in late April 2009 new observations made by the original discovery team concluded that the planet is on the outskirts of the habitable zone where liquid water may exist. In May 2011 researchers in France released a study of a three-dimensional climate simulation concluding that it is plausible that the planet has a stable atmosphere and liquid water on the surface, concurring that it is the first discovered terrestrial-mass exoplanet in the habitable zone, followed by HD 85512 b several months later. (From Wikipedia)