On the evolution of accretion disc flow in cataclysmic variables - III. Outburst properties of constant and uniform-  model discs

Abstract

The authors examine the stability and evolution of some simple accretion disc models in which the viscosity is prescribed by an ad hoc uniform-α model. They are primarily concerned with systems in which the mass-input rate from the secondary to the disc around the primary, M*, is assumed to be constant. However, initial calculations with variable mass-input rates are also performed. The time-dependent visual magnitude light-curves are constructed for cataclysmic binaries with a range of disc size, primary mass, mass-input rate, and magnitude of viscosity (i.e. value of α). Comparisons are made between these theoretical results and the observed properties of various subclasses of cataclysmic variables. These results indicate that the observational differences between novae and dwarf novae may be due to differences in the mass-input rate. The authors' models can reproduce the gross observational features of U Gem-type dwarf-novae outbursts. For SS Cyg and Z Cam systems, modestly variable mass-input rates may also be required.