EK TrA, a close relative of VW Hyi

Abstract

The southern dwarf nova EK TrA has been suggested to show the spectrum of its white dwarf primary in the single available International Ultraviolet Explorer (IUE) post-outburst spectrum. We demonstrate that this spectrum is still disc-dominated. However, a careful analysis reveals a white dwarf contribution of -25 per cent of the SWP flux and a white dwarf temperature of T wd = 18 000 K. Our optical spectroscopy of the system deep in quiescence confirms the flux level of the white dwarf derived from the IUE data. Additional optical emission arises from a cool (T = 6500 K) accretion disc, possibly extending over the whole Roche lobe radius of the primary. Both optical and UV data yield a distance of d = 180pc.