EVOLUTION OF NEUTRON-STARS IN HIGH-MASS X-RAY BINARIES

We consider the evolution of neutron stars during the X-ray phase of h igh-mass binaries. Calculations are performed assuming a crustal origi n of the magnetic field. A strong wind from the companion can signific antly influence the magnetic and spin behaviour of a neutron star even during the main-sequence life of the companion. In the course of evol ution, the neutron star passes through four evolutionary phases ('isol ated pulsar', propeller, wind accretion, and Roche lobe overflow). The model considered can naturally account for the observed magnetic fiel ds and spin periods of neutron stars, as well as the existence of puls ating and non-pulsating X-ray sources in high-mass binaries. Calculati ons also predict the existence of a particular sort of high-mass binar y with a secondary that fills its Roche lobe and a neutron star that d oes not accrete the overflowing matter because of fast spin.