Evolution of neutron stars in high-mass X-ray binaries

Abstract

We consider the evolution of neutron stars during the X-ray phase of high-mass binaries. Calculationsareperformedassumingacrustal originofthemagneticfield.Astrongwindfrom the companion can significantly influence the magnetic and spin behaviour of a neutron star even during the main-sequence life of the companion. In the course of evolution, the neutron star passes through four evolutionary phases (‘isolated pulsar’, propeller, wind accretion, and Roche lobe overflow). The model considered can naturally account for the observed magnetic fields and spin periods of neutron stars, as well as the existence of pulsating and non-pulsating X-ray sources inhigh-mass binaries. Calculationsalso predict the existence of a particular sort of high-mass binary with a secondary that fills its Roche lobe and a neutron star that does not accrete the overflowing matter because of fast spin.