The evolutionary history of X-ray binaries

Mass transfer processes in X-ray binaries are discussed, and some refined considerations about Roche-lobe overflow are presented. The pulsating X-ray sources with long pulse periods (slow pulsars) such as X Persei are examined; and it is suggested that these sources are neutron stars whose rotation has been slowed down by electromagnetic friction with a stellar wind. The effects of mass loss and tidal friction on the evolution of X-ray binaries are discussed. It is suggested that the primaries of these binaries may be overluminous as a result of mass loss in stellar winds. (R.S.)