A visible and infrared study of the eclipsing dwarf nova OY Carinae.-I. The visible eclipses of the central object.

This paper presents four visible light curves of the highly inclined, short-period cataclysmic binary star OY Carinae in quiescence. These light curves show that the red dwarf eclipses both its white dwarf companion and the accretion disc and hotspot, which originate from material transferred from the red dwarf to the white dwarf. An analysis of the eclipse of the white dwarf, under the asumption that its red dwarf companion fills its Roche lobe, gives the following properties of the system when combined with the observed radial velocity amplitude of the white dwarf: the inclination lies between 73.5 deg and 81, the mass of the white dwarf lies between 0.4 solar mass and 1.4 solar mass, and the red dwarf lies either on or slightly below the lower main-sequence mass-radius relation. This range of properties is somewhat larger than found in previous analyses, where the uncertainties in the poorly known semiamplitude of the radial velocity of the white dwarf were not taken fully into account. The consequences of the present findings are discussed in the light of current ideas about the evolution of cataclysmic variable stars.