Speaker
Ali Alpar
(Sabanci University)
Description
The determination of the inner radius of an accretion disk needs to take into account the rotation rates of the disk and the neutron star and the angular momentum exchange between the disk and the star. When angular momentum is taken into account, with conditions to accrete or expel matter, the inner radius is found to lie closer to the corotation radius, rather than the Alfven radius, especially in propeller sources, and transitional sources. The model explains the transitions between strong and weak propeller stages, with spin-down and accretion with spin-up, respectively; the associated X-ray luminosities and spin-down - spin-up rates observed in transitional millisecond pulsars and LMXB evolution.
Author
Ali Alpar
(Sabanci University)