THEORETICAL LIGHT-CURVE FOR THE RECURRENT NOVA RS OPHIUCHI - DETERMINATION OF THE WHITE-DWARF MASS, COMPOSITION, AND DISTANCE

Sequences of steady mass-loss solutions are constructed for the envelopes on a white dwarf with mass 1.33, 1.35, 1.36, 1.37, and 1.377 M. as models of the decay phase of novae. The envelopes are assumed to have a uniform chemical composition with X = 0.73, 0.6, 0.52, 0.44, 0.33, and 0.11 for hydrogen and Z = 0.02 for heavy elements by weight. An excellent agreement with the observed light curves of UV and optical is obtained in the models with a white dwarf mass of 1.36 M. with hydrogen content X = 0.52, and 1.37 M. with X = 0.6. The distance to RS Oph is obtained to be 1.6 kpc from the comparison between the theoretical and observed light curves. The success of this wind model is a strong indication from the theoretical point of view that RS Oph is a thermonuclear runaway event.