Analysis of Photometric Observations of the New Cataclysmic Variable ASASSN-13cx

Abstract

Photometric observations of the variable star ASASSN-13cx acquired in the course of a program of studies of cataclysmic variables and their parameters recently carried out at the Sternberg Astronomical Institute (SAI) are presented. The star was observed with the 50-cm and 60-cm telescopes of the SAI Crimean Astronomical Station and a CCD photometer (similar to 1800 images in the V and Rc filters) during the variable's outburst of August-September 2014 and in a period of quiescence in October-November 2016. The ASASSN-13cx system is confirmed to be a SU UMa variable. Parameters of the system are derived from eight light curves using a "composite" model that takes into account the presence of a hot spot on the lateral surface of the geometrically thick disk and of a region of enhanced energy release near the disk edge, at the base of the gas flow (the so-called "hot line"). Parameters of the system for three light curves during the outburst were obtained in the framework of a "spiral" model that additionally takes into account the presence of geometric perturbations on the accretion-disk surface. The parameters of ASASSN-13cx determined using these models provide good accuracy in reproducing the system's light curves in both states. The basic parameters of the system have been determined for the first time: the component mass ratio q = M (1)/M (2) = 7.0 +/- 0.2, the orbital inclination i = 79.9A degrees-80.1A degrees, the distance between the components' centers of mass a (0) = 0.821(1) R (Ey), and the sizes and temperatures of the stars: R (1) = 0.0124(5)a (0) = 0.0102(4) R (Ey), T (1) = 12 500 +/- 280 K, aEuroR (2)aEuroe = 0.236(4)a (0) = 0.194(3) R (Ey), T (2) = 2550 +/- 400 K, corresponding to M4-9V for the spectral type of the secondary. Parameters of the accretion disk have been derived for both activity states. The mass of matter in the accretion disk increased by almost a factor of two during similar to 400 orbital periods in quiescence.