Upsilon Andromedae

Upsilon Andromedae (υ Andromedae / Ups And) is a binary star, somewhat younger than the Sun, and is approximately 44 light-years away in the constellation Andromeda. The system contains a yellow-white dwarf star (Upsilon Andromedae A) similar to the Sun and a dim red dwarf (Upsilon Andromedae B). The two stars are separated by around 750 times the distance from the Earth to the Sun.

As of 1999, three extrasolar planets are known in orbit around Upsilon Andromedae A. All three are comparable to Jupiter in mass. Upsilon Andromedae was both the first multiple-planet planetary system to be discovered around a main sequence star, and the first multiple-planet system known in a multiple star system.

Upsilon Andromedae A is ranked 21st in the list of top 100 target stars for the NASA Terrestrial Planet Finder mission.