Gliese 876 b

Gliese 876 b is an exoplanet orbiting the red dwarf Gliese 876. Given the planet is 2.276 times more massive than Jupiter, it is likely that it is a gas giant with no solid surface. Gliese 876 b currently lies beyond the outer edge of the habitable zone but because Gliese 876 is a slowly evolving red dwarf its habitable zone is slowly moving outwards. Therefore, Gliese 876 b will, in trillions of years time, lie inside Gliese 876's habitable zone and remain there for at least 4.6 billion years. While the prospects for life on a gas giant are unknown, large moons may be able to support a habitable environment. Models of tidal interactions between a hypothetical moon, the planet and the star suggest that large moons should be able to survive in orbit around Gliese 876 b for the lifetime of the system. The large mass of the gas giant may also make it more likely for larger moons to form. While no moons of Gliese 876 b have been observed or measured as of yet, if they exist they would be good terraforming candidates, and at only 15.3 light years from Earth, they could be reached in a forseeable future.