Some Properties of White Dwarf Collapse in Low Mass Binaries

Conditions for collapse of an accreting white dwarf in a low-mass close binary are analysed. It is shown that if the magnetic strength on the surface of a white dwarf is less than 10⁵–10⁶ G, a rotation barrier appears which prevents the direct formation of a neutron star. As a result, a time-scale for the collapse is defined by a specific time of momentum dissipation rather than by free-fall time-scale. It is noted that a tidal deformation of a white dwarf, intensified in a process of collapse, renders collapse in a low-mass close binary sharply anisotropic. Consequently fast moving radiopulsars can arise with velocities of some thousands km s^‑1.