Evolution of the accretion disk in black hole X-ray transients

Several black hole X-ray transients have a very long recurrence time, decades of years. We study the evolution of the disk during quiescence and interpret the outburst behaviour as a marginal occurrence of a dwarf nova type disk instability in the cool outer accretion disk. We determine the amount of mass stored in the disk until the triggering of the outburst and the recurrence time. The evaporation of matter from the inner accretion disk to a coronal flow is an essential feature of the disk evolution and depends on the black hole mass. For accretion rates slightly lower than those in the known black hole X-ray transients the disk would be stationary, the systems would persistently remain in a cool state. (orig.)SIGLEAvailable from TIB Hannover: RR 4697(1259) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman