 The innermost planet of the Upsilon Andromedae system was discovered in 1996 and announced in January 1997 , together with the planet of Tau Boötis and the innermost planet of 55 Cancri . The discovery was made by Geoffrey Marcy and R. Paul Butler , both astronomers at San Francisco State University . The planet , designated Upsilon Andromedae b , was discovered by measuring changes in the star 's radial velocity induced by the planet 's gravity . Because of its closeness to the parent star , it induced a large wobble which was detected relatively easily . The planet appears to be responsible for enhanced activity in the chromosphere of its star . 
