Evidence for Multiple Companions to

1 Based on observations obtained at Lick Observatory, operated by the University of California, and at the Whipple Observatory, operated by the Smithsonian Astrophysical Observatory. ABSTRACT The bright F8 V star Andromedae was previously reported to have a 4.6 day Doppler velocity periodicity, consistent with a Jupiter{mass companion orbiting at 0.059 AU. Follow{up observations by both the Lick and AFOE planet survey programs connrm this periodicity, and reveal additional periodicities at 242 and 1269 days. These periodicities are consistent with Keplerian orbital motion, and imply two additional companions orbiting at 0.83 and 2.5 AU, with minimum (M sin i) masses of 2.0 and 4.1 Jupiter-masses respectively. Non{Keplerian explanations for the observed Doppler velocity variations are examined, including radial and nonradial pulsations, rotational modulation of surface features, and stellar magnetic cycles. These explanations seem unlikely based on the observed photometric and chromospheric stability of the star. This putative three planet system is found to be dynamically stable by both analytic techniques and numerical simulations. The outer two companions both reside in eccentric orbits, as do all 9 known extrasolar planet candidates in distant orbits. If real, this multiple{planet system is the rst around a main-sequence star, and its study should ooer insights into planet formation, planet{planet interactions, and the observed eccentricities of planetary orbits.