2009PASP..121..811A

The Barr Effect is a nonrandom distribution of longitudes of periastron, ω, in spectroscopic binary orbits. Physically one would not expect elliptical binary orbits to show any preferred orientations. Aitken and Struve have shown a preference for 0 < {omega] < 90{deg }among 275 elliptical binary orbits of all primary types. Some eclipsing binaries show inconsistencies between their light and velocity curves. Struve showed that the velocity curves of some spectroscopic binaries are distorted by absorption in gaseous streams flowing between the components. I wondered about the occurrence of this effect for stars of various spectral types and found that the effect occurs primarily for B0-B3 V-lll primaries but may be present in a few of the remaining BA stars. The B0-B3 region is also where the mean radial velocities of stars (single plus binaries) in open clusters are systematically larger than for other stars.