A Far-Ultraviolet Study of the Hot White Dwarf in the Dwarf Nova WW Ceti

Abstract

We present a synthetic spectral analysis of IUE archival and FUSE (Far Ultraviolet Spectroscopic Explorer) far-UV spectra of the peculiar dwarf nova WW Cet. During the quiescence of WW Cet, a white dwarf with T_wd~26,000+/-1000 K can account for the far-UV flux and yields the proper distance. However, the best agreement with the observations is provided by a two-temperature white dwarf model with a cooler white dwarf at T_wd=25,000 K providing 75% of the far-UV flux and a hotter region (accretion belt or optically thick disk ring) with T=40,000 K contributing 25% of the flux for the proper distance. We find from the FUSE spectrum that the white dwarf is rotating with Vsini=600+/-100 km s^-1. Our temperature results provide an additional data point in the distribution of WD T_wd versus orbital period above the CV period gap, where few WD T_wd values are available.

Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer. FUSE is operated for NASA by the Johns Hopkins University under NASA contract NAS5-32985.