 The planet was claimed to be detected by astronomers in the Lick @-@ Carnegie Exoplanet Survey , led by principal investigator Steven S. Vogt , professor of astronomy and astrophysics at the University of California , Santa Cruz and co @-@ investigator R. Paul Butler of the Carnegie Institution of Washington . The discovery was made using radial velocity measurements , combining 122 observations obtained over 11 years from the High Resolution Echelle Spectrometer ( HIRES ) instrument of the Keck 1 telescope with 119 measurements obtained over 4 @.@ 3 years from the High Accuracy Radial Velocity Planet Searcher ( HARPS ) instrument of the European Southern Observatory 's 3 @.@ 6 m telescope at La Silla Observatory . 
