Wind Accretion vs Roche Lobe Overflow in HMXBs

Abstract

We present a series of time-dependent 2D and 3D numerical simulations illustrating the evolutionary sequence between high mass X-ray binaries fed by wind accretion (where the primary star sits well within its critical tidal lobe) and those fed by Roche lobe overflow (where the primary star extends out to its tidal lobe). When the primary lies well within its critical surface we find negligible tidal mass loss enhancement, and a system that is characterized by wind accretion with the development of a photoionization zone around the compact object. As the surface of the primary nears the critical surface, we observe tidally enhanced mass loss via a thin tidal stream, resulting in higher accretion wake densities. For full RLOF we observe the development of a steady accretion disk characterized by a total shadowing of the X-rays in the orbital plane.