Signs of magnetic accretion in X-ray pulsars

The spin-down mechanism of accreting neutron stars is discussedwith an application to one of the best studied X-ray pulsars GX301-2. We show that the maximum possible spin-down torque applied to a neutron star from the accretion flow can be evaluated as K _sd ^(t) = ??²/(r _m r _cor)^3/2. The spin-down rate of the neutron star in GX301-2 can be explained provided the magnetospheric radius of the neutron star is smaller than its canonical value. We calculate the magnetospheric radius considering the mass-transfer in the binary system in the frame of the magnetic accretion scenario suggested by V.F. Shvartsman. The spin-down rate of the neutron star expected within this approach is in a good agreement with that derived from observations of GX301-2.