ИСТИНА

Cataclysmic variables represent a large class of close binary systems in the late stages of evolution. They consist of a white dwarf (the primary component) and an evolved star of late spectral class K-M (the secondary component) filling the Roche lobe. For the evolutionary stage of the CV-s is characterized by a quasi-constant flow of the substance of the secondary, experiencing evolutionary expansion, to the primary component through the inner point of the Lagrange. At low magnetization of CV-s (< 106 G), an accretion disk is formed around it, which provides dissipation of the momentum of the flowing substance. From the observations made for different activity states of the system, within the framework of the relevant models, it is possible to obtain the values of the system parameters. Different models take into account the presence in the system of 1). the classical hot spot on the outer side of the disk, 2). hot line (gas flow) located outside the disk, 3). and a complex consisting of a hot line and a classic hot spot. The latter model makes it possible to interpret well various light curves of CV-s in a quiet state, sometimes in active or intermediate states with undistorted geometry of the inner surface of the disk. In case of presence of geometrical distortions on a surface of a disk the model with spiral sleeves on a disk is used. We used the Nelder–Mead method to solve for the system parameters that best match the shapes of the synthetic and observed light curve. As a result of our analysis, the parameters of the accretion disk - radius, thickness of the outer edge of the disk, the temperature of the inner areas of the disk, the parameters of the hot spot and the hot line and the contribution of radiation of various components to the total luminosity of the system are determined. The orbital periods of some cataclysmic variables are obtained from the new data. The contributions of different radiation sources to the total luminosity of the system are estimated. To explain the outbursts of the dwarf novae proposed two models: model of instability of the mass transfer (MTIM) and the model thermoviscous disc instability (DIM). The data we have obtained allow us to conclude from what is the cause of the outburst in a particular system.