Accretion behaviour in SS Cygni.

Abstract

The He II (1640 A) equivalent widths are determined from 28 IUE short wavelength low resolution spectra of SS Cygni in quiescence and in outburst. By using the boundary layer model for cataclysmic variables (Patterson and Raymond 1985), the mass accretion rate M(He II) is derived. This mass accretion rate is practically coincident with the rate of mass accretion onto the white dwarf. Its value, during quiescent phases of the system, is also dependent on the type of the preceding outburst. This casts some light on the behavior of the system outburst cycles.