gliese 581 c is a exoplanet that orbits the red dwarf star gliese 581. it is located about 20 light years away in the libra. it is about six times as massive as earth, and circles its star about 11 million kilometers from it (the earth is 150 million kilometers away from the sun). it takes it 13 days to circle the star once. when it was discovered in 2007, it was thought to be earth-like and habitable.