Application of magnetic braking theories to black hole binaries

Abstract

Many of the recently‐discovered soft x‐ray transients are also black hole candidates; I explore the possibility that magnetic braking, a plausible driving mechanism of mass transfer in these systems, may naturally lead black hole systems to become transients. I show that, regardless of the details, magnetic braking leads to a lower accretion rate for black hole primary with masses substantially greater than 1.4 M⊙ than for neutron star binaries.