Outburst Characteristics in the Dwarf Nova SU Ursae Majoris

Abstract

the 1973-1999 V0band light curve from AAVSO visual estimates and RoboScope CCD exposures is examined to study the systematic properties of normal outburst and superoutbursts in this prototype of the SU UMa-type dwarf novae. A number ofthe outbrusts's correlation previously reported in VW Hyi and in SU UMa are not present in these data. several lines of evidence suggest that, during this 26 years interval, variation in the mass-transfer rate served to obsucre some of the expected correlations. the Mdot variation apparently caused as nearly complete cessation of outbursting in 1980-1983. We do find a correlation of the time sice the last superoutburst with the mean brightness in the interaval since the last superoutburst, supporting the notion that superoutbursts are a disk-initiated phenomenon that occurs when the gas remainning in the disk after each normal outbursts has accumulated to some critical value.