Dwarf novae in outburst : modelling the observations.

Abstract

Time-dependent accretion-disk models are constructed and used to calculate theoretical spectra in order to try and fit the ultraviolet and optical observations of outbursts of the two dwarf novae VW Hydri and CN Orionis. It is found that the behavior on the rise to outburst is the strongest discriminator between theoretical models. The mass-transfer burst model is able to fit the spectral behavior for both objects. The disk-instability model is unable to fit the rise to outburst in VW Hydri, and gives a poor fit to the observations of CN Orionis. The accuracy of the modelling procedures and how they might be improved are discussed, and the implications of the findings are commented on.