47 Ursae Majoris planets. Artwork comparing the orbits (orange) of two planets discovered orbiting the star 47 Ursae Majoris (47 UMa), and the orbits (blue) of Jupiter, Mars and Earth around our Sun. The two 47 UMa planets would orbit between Mars and Jupiter if placed in our solar system. 47 UMa b, the inner planet, was discovered in 1995, has a mass of 2.5 Jupiters and orbits in 3 years. 47 UMa c, discovered in 2001, has a mass of 0.75 Jupiters and orbits in 7 years. 47 UMa is a nearby Sun-like star. Unlike most extrasolar planets detected, these have circular orbits outside the habitable zone, but it is thought that their closeness to this zone has prevented Earth-like worlds forming.