Saul G. Levy

The frequency and formation mechanism of B2-B5 main-sequence binaries

Twenty coude spectra were obtained for each of the 74 B2-B5 IV or V stars, and the results of their radial velocities were combined with those of a previous study of 42 similar stars, to examine the frequency and the formation mechanism of these binaries. New improved orbital elements are listed for nine known double-lined and 26 single-lined spectroscopic binaries. It is found that, systems with periods of 0.01 yr to 100,000 yrs, have secondary frequencies that fit the Salpeter (1955) luminosity function (but not the van Rhijn function), indicating that these systems were formed primarily by capture. For systems with periods shorter than 0.01 yr, the separations of components are only a few stellar radii, suggesting that these systems have undergone mass transfer; their secondary masses have no direct information concerning the formation mechanism. 53 refs.

Improved study of metallic-line binaries

Nouvelle etude de la frequence de binaires parmi les etoiles Am a raie metallique classiques et des caracteristiques de ces systemes

Visual multiples. I. ADS 7251

This wide pair of dM 0.5 stars is found to have extremely strong Ca II emission lines. Probably each component is a spectroscopic binary and orbital elements are given. The masses derived seem consisient with those determined in the astrometric study by Chang (1972).