Binaries among B2 - B5 IV, V absorption and emission stars.

Samples of 42 B2-B5 IV or V and 21 B2e-B5e IV or V stars are studied on the basis of 20 coude spectra of each star for evidence of spectroscopic binaries. Orbital elements are derived for eight newly discovered binaries among the B stars and two among the Be stars, orbital elements are confirmed or improved for four other systems, and the apsidal motion of two stars is examined. The upper limit in separation for common-proper-motion (CPM) pairs is investigated, periods are estimated for three CPM systems with orbital elements, and the statistics of the observed multiples is evaluated. It is shown that there are 20 singles (51 percent), 14 doubles (36 percent), and five triples (13 percent) in a reduced sample of 39 B stars, as well as 15 singles (75 percent), four doubles (20 percent), and one triple (5 percent) in a reduced sample of 20 Be stars. The B and Be stars are found to differ in one major respect: there are no known Be binaries in the sample with periods of less than about 100 days, but half the B-star multiples have periods of less than 100 days. An assessment is made of the number of binaries missed because their velocity variations are small due to small orbital inclinations or small secondary masses.