 Like the majority of known extrasolar planets , Upsilon Andromedae b was detected by the variations in its star 's radial velocity caused by the planet 's gravity . The variations were detected by making sensitive measurements of the Doppler shift of Upsilon Andromedae 's spectrum . The planet 's existence was announced in January 1997 , together with 55 Cancri b and the planet orbiting Tau Boötis . 
