Spectroscopic Orbit for a Very Metal-Deficient Star, the Subdwarf BD + 13 Deg 3683

摘要

The subdwarf BD + 13 3683 was observed with the radial-velocity scanner CORAVEL. Peak-to-peak radial-velocity variations of 50 km/sec are reported. A spectroscopic orbit was determined: BD + 13 3683 is apparently the most metal-deficient star (Fe/H = 2.3) with known orbital elements. This period is 40 days and the companion is expected to have a mass greater than 0.4 solar mass.