Ana Lourdes Juarez Garcia

Hydrodynamic simulations of accretion disks in X-ray binary progenitors

To have a better understanding of the progenitors in X-ray binaries (specially low-mass and intermediate mass X-ray binaries), we need to consider the dynamics and outcomes of the steps that both stars in the binary go through in their respective and combined (interacting) evolutions. One important phase is the formation of an accretion disk via mass transfer, after the primary has already become a neutron star and the companion has become a giant that transfers mass to the neutron star. This happens before the system goes into common envelope (CE) phase. We need to understand the formation, evolution and longevity of the disk and what the impact of the disk (and possible jets) is on the CE phase that follows. So far analytical studies of the mass transfer phase, and a handful of hydrodynamic simulations (including global CE simulations) attempt to answer these questions but with very poor results. I present 3D hydrodynamic simulations of the formation of an accretion disk around a 1.4 Mo, NS in an intermediate mass X-ray binary with a 7 Mo red supergiant using a grid and an SPH code. I show the mass transfer phase is more complex than assumed and I constrain the disk parameters including size, mass, scale height and longevity.