2003ApJ...590..445H

A new self-sustained model for long-term light-curve variations of RX J0513.9-6951 is proposed based on an optically thick wind model of mass-accreting white dwarfs (WDs). When the mass accretion rate to a WD exceeds the critical rate of ∼1x10^–6 M_☉.yr^–1, optically thick strong winds begin to blow from the WD so that a formation of common envelope is avoided. The WD can accrete and burn hydrogen-rich matter on the surface of the WD at the critical rate. The excess matter transferred to the WD above the critical rate is expelled by winds. This is called ``accretion wind evolution.'' This ejection process, however, occurs intermittently because the mass transfer is attenuated by strong winds: the strong winds collide with the secondary surface and strip off the surface layer of the secondary. The stripped-off matter is lost from the binary system. Properly formulating this mass-stripping effect and the ensuing decay of mass-transfer rate, we are able to reproduce, in a self-sustained manner, the transition between the optical high/X-ray-off and optical low/X-ray-on states of RX J0513.9-6951. Thus RX J0513.9-6951 is the first example of accretion wind evolution, which is a key evolutionary process in a recently developed evolutionary path to Type Ia supernovae.