A MODEL FOR WZ-SGE WITH STANDARD VALUES OF ALPHA

We present a model for the dwarf nova WZ Sge which does not require as sumption of unexplained and unusually low values of the viscosity alph a-parameter during exceptionally long quiescent states of this system. We propose that the inner parts of the accretion disc are disrupted b y either a magnetic field or evaporation, so that the disc is stable ( or very close to being stable) in quiescence, as the mass transfer rat e is very low and the disc can sit on the cool, lower branch of the th ermal equilibrium curve. Outbursts are triggered by an enhanced mass t ransfer, which brings the disc into the unstable regime of the standar d dwarf nova disc instability model, The resulting eruptions are stron gly affected by the irradiation of the secondary star. Our model repro duces very well the recurrence time and the characteristics of the lig ht curve in outburst.