7. Gliese 163c The mass of Gliese 163c puts the planet in a gray zone. The planet is seven times the mass of Earth, which could make it a very large rocky planet or a dwarf gas giant. Gliese 163c whirls around its dim planet star every 26 days, at a distance of 50 light-years away from Earth. Its parent star is in the constellation Dorado.