Long-term optical photometry of the dwarf nova VW Hyi

Abstract

Long-term five-colour photometry of the dwarf nova VW Hyi shows no evidence for a secular change of the flux during the quiescent interval between normal outbursts (3σ upper limits between 0.16 and 0.20 mag in the five passbands). However, the amplitudes in the orbital B-U and U-W colour curves change during quiescence. A delay in the progress of normal outbursts toward higher frequencies confirms the delay, seen with IUE, in the onset of a normal outburst towart higher frequencies. Just after outburst, the system is substantially bluer than later in quiescence.