Radial Velocities of B-Type Stars in the Nearest Associations.

Abstract

Radial velocities are given for 59 0- and B-type stars in the associations I Lac, I Ori, II Per, and in the Cas-Tau region, together with a few field stars They are based on 1040 spectrograms obtained with the 82-inch McDonald telescope in the years 1952-1956 The principal purpose of the program was, to obtain more complete information on the incidence of spectroscopic binaries in these groups. Orbital elements are given for eleven spectroscopic binaries for which no elements had been published previously For all but two of these, the semiamplitude of the velocity variation lies between 10 and 40 km/sec. Knowledge of the spectroscopic binaries among the stars of spectral types B5 and earlier in the groups mentioned may now be regarded as nearly complete for objects with periods below 50 days and semiamplitudes K1 exceeding 10 km/sec The results of this work serve for a statistical discussion of the properties of the binaries in stellar associations to be published separately.