HD 137510: An Oasis in the Brown Dwarf Desert

Since the beginning of precise Doppler surveys, which have had stunning success in detecting extrasolar planetary companions, one surprising enigma has emerged: the relative paucity of spectroscopic binaries where the secondary mass lies in between the stellar and planetary mass regime. This gap in the mass function for close-in (a < 3-4 AU) companions to solar-type stars is generally referred to as the "brown dwarf desert." Here we report the detection of a companion to HD 137510 (G0 IV), with a minimum mass of 26M sub(J), moving in an eccentric orbit (e = 0.4) with a period of 798 days and an orbital semimajor axis of 1.85 AU. The detection is based on precise differential radial velocity data obtained by the McDonald Observatory and Thueringer Landessternwarte Tautenburg planet search programs.