2008MNRAS.385L...1S

In this Letter, the radial velocity variability of the chemically peculiar star ε Ursae Majoris (εUMa) from the sharp cores of the hydrogen lines is investigated. This study is based on the ELODIE archival data obtained at different phases of the rotational cycle. The star exhibits low-amplitude radial velocity variations with a period of P = 5.0887 d. The best Keplerian solution yields an eccentricity e = 0.503 and a minimum mass of ∼14.7M_Jup based on the hypothesis that the rotational axis of ε UMa is perpendicular to the orbital plane. This result indicates that the companion is the brown dwarf with the projected semi-amplitude variation in the radial velocity K₂= 135.9 km/s and the sine of inclination time semimajor axis a₂sin(i) = 0.055 au.