Critical period of a star in the scenario of accretion-driven spin-up

Abstract

We consider the accretion-driven spin-up of a magnetized degenerate star in a close binary system under different assumptions about the accretion scenario. We have estimated the minimum possible spin period which the star can achieve in the course of such spin-up. We show that the star can achieve the minimum possible value of the spin period if the interchange instabilities of its magnetospheric boundary are suppressed.