An extrasolar planet or exoplanet is a planet orbiting a star (or remnant of a star) beyond our Solar System. As of autumn 2007, about 250 exoplanets had been discovered around 220 different stars, including nearly two dozen multiple planet systems. No less than five exoplanets have been discovered orbiting the star 55 Cancri; one of the planets has nearly four times the mass of Jupiter, another is comparable with Jupiter in mass, two are slightly less massive than Saturn, while the innermost planet has a mass similar to that of Uranus
