ИСТИНА

The parameters of the dwarf nova SS Cyg are found as an inverse problem solution using the mean UBV-light curves obtained in quiescence. We used a close binary system model with a geometrically thick symmetric disk around a white dwarf. Masses and radii of the system components are determined. It is shown that the white dwarf mass in SS Cyg is about 1.5 times larger than the red dwarf one: q=Mwd/Mrd ~ 1.45, Mrd~0.40-0.53Mo and Mwd~0.62-0.73Mo. The spectral type of the red dwarf, K3-5V, obtained from photometric data, agrees with results derived from absorption line analysis. The orbital inclination i is 52deg. We also estimated the contribution of the accretion disk radiation to the total flux of the system in quiescence. In V band it is nearly the same as the red component flux and about 1.5 and 1.6 times larger in B and U bands, respectively. The contribution of hot spot to the total flux in optical range does not exceed 5-10% of red dwarf flux. The shape of SS Cyg mean light curves in quiescence can be explained by an asymmetric heating of the red dwarf surface by X-ray radiation from the hot spot region.