1998ApJ...505L.147M

Doppler measurements of the M4 dwarf star Gliese 876 taken at both Lick and Keck Observatories reveal periodic, Keplerian velocity variations with a period of 61 days. The orbital fit implies that the companion has a mass of M=2.1 M_JUPMsini, an orbital eccentricity of e=0.27±0.03, and a semimajor axis of a=0.21 AU. The planet is the first found around an M dwarf and was drawn from a survey of 24 such stars at Lick Observatory. It is the closest extrasolar planet yet found, providing opportunities for follow-up detection. The presence of a giant planet on a noncircular orbit, 0.2 AU from a 0.32 M_☉ star, presents a challenge to planet formation theory. This planet detection around an M dwarf suggests that giant planets are numerous in the Galaxy.