MAGNETIC AND SPIN EVOLUTION OF NEUTRON-STARS IN CLOSE BINARIES

The evolution of neutron stars in close binary systems with a low-mass companion is considered, assuming the magnetic field to be confined w ithin the solid crust. We adopt the standard scenario for the evolutio n in a close binary system, in which the neutron star passes through f our evolutionary phases ('isolated pulsar' -'propeller' -accretion fro m the wind of a companion -accretion resulting from Roche-lobe overflo w). Calculations have been performed for a great variety of parameters characterizing the properties of both the neutron star and the low-ma ss companion. We find that neutron stars with more or less standard ma gnetic field and spin period that are processed in low-mass binaries c an evolve to low-held rapidly rotating pulsars. Even if the main-seque nce life of a companion is as long as 10(10) yr, the neutron star can maintain a relatively strong magnetic field to the end of the accretio n phase. The model that is considered can account well for the origin of millisecond pulsars.