Mass-stream trajectories with non-synchronously rotating donors

Abstract Mass-transfer interactions in binary stars can lead to accretion disk formation, mass loss from the system and spin-up of accretor. To determine trajectory mass-transfer stream, whether it directly impacts accretor, or forms an disk, requires numerical simulations. The stream is approximately ballistic, analytic approximations based on such trajectories are used many population synthesis codes as well detailed stellar evolution codes. We use explore conditions under which transfer takes place. then solve reduced three-body equations compute a particle for systems with varying ratio, donor synchronicity initial velocity. Our results show that average both more time spent during sub-synchronous than synchronous donor. Moreover, we find at low velocity asynchronous rotation leads self-accretion over large range ratios, especially super-synchronous donors. (self-)intersects narrow region parameter space where transitions between accreting onto Increasing larger areas accretes but also (self-)intersection. radii closest approach generally increase, specific angular momenta these carry radius gets broader. made publicly available.