1998 Superoutburst of the Large-Amplitude SU UMa-Type Dwarf Nova WX Ceti

Abstract

Abstract We observed the 1998 November superoutburst of WX Cet, a dwarf nova originally proposed as a WZ Sge-like system. The observation established that WX Cet is an SU UMa-type dwarf nova with a mean superhump period of 0.05949(1)d, which is 2.1% longer than the reported orbital period. The lack of early superhumps at the earliest stage of the superoutburst, the rapid development of usual superhumps, and the possible rapid decay of late superhumps seem to support that WX Cet is a fairly normal large-amplitude SU UMa-type dwarf nova, rather than a WZ Sge-type dwarf nova with a number of peculiarities. However, a period increase of superhumps at a rate $\dot{P}/P = +8.5\pm 1.0 \times 10^{-5}$ was observed, which is one of the largest $\dot{P}/P$ ever observed in SU UMa-type dwarf novae. A linear decline of light, with a rate of $0.10 \,\mathrm{mag} \,\mathrm{d}^{-1}$, was observed in the post-superoutburst stage. This may be an exemplification of the decay of the viscosity in the accretion disk after the termination of a superoutburst, mechanism of which is proposed to explain a variety of post-superoutburst phenomena in some SU UMa-type dwarf novae.