<Li> Gamma Cephei Ab : The radial velocity variations of the star Gamma Cephei were announced in 1989 , consistent with a planet in a 2.5 - year orbit . However , misclassification of the star as a giant combined with an underestimation of the orbit of the Gamma Cephei binary , which implied the planet 's orbit would be unstable , led some astronomers to suspect the variations were merely due to stellar rotation . The existence of the planet was finally confirmed in 2002 . </Li>
the first series of extrasolar planets that were discovered were found by which method
radial velocity variations