IUE observations of dwarf novae during active phases.

Abstract

Spectra of six dwarf novae during active phases were observed with the IUE in the low resolution mode in order to study different types of outburst behavior and to investigate physical processes during outbursts. Results were obtained for continuum energy distribution and interstellar extinction, temperatures and spectral indices, line spectra, and mass loss. There is an obvious tendency that the flattest spectral energy distributions occur in those objects in the sample with the largest mass loss rates. This is interpreted as bolometric flux redistribution of hot disk radiation in the expanding envelope around active dwarf novae. This model could provide a possible physical explanation of the standstill phenomenon in many dwarf novae.