The 1985 May superoutburst of the dwarf nova OY Carinae – II. IUE and EXOSAT observations⋆

We present ultraviolet (IUE) and X-ray (EXOSAT) observations of the eclipsing dwarf nova OY Carinae during the superoutburst of 1985 May. From the lack of X-ray eclipse and UV behaviour we deduce that the X-ray flux originates in an optically thin corona comparable in size to the Roche lobe, and not directly from the white dwarf or boundary layer. The asymmetric UV line emission originates partly in the accretion disc and partly in a wind. There is a strong modulation of the UV continuum flux that the authors suggest is caused by extended vertical disc structure shadowing the inner regions.