Outburst activity of the intermediate polar DO Draconis (3A 1148+719)

An analysis of the long-term light curve of the intermediate polar DO Dra is presented. The courses of the outbursts were resolved and their light curves are analyzed. The decays of the respective outbursts are faster than exponential. The decay rate τ_D = 0.92 days mag_vis^-1 in comparison with 1.68 days mag_vis^-1 for non-magnetic systems and suggests that the magnetosphere is not fully compressed during the outburst of DO Dra. The typical recurrence time T_C of outbursts over the last 63 years is found to be 870 days, the standard deviation of most outbursts being 100 days. The quiescent level displays fluctuations on the time scale of tens and hundreds of days without any apparent trend between the neighbouring outbursts. This research has made use of the AFOEV database, operated at CDS (France), VSNET database (Japan) and VSOLJ database (Japan).