Photometric behavior of the cataclysmic variable SDSS J150240.98+333423.9/NZ Boo in quiescence

Abstract

An analysis of V photometric light curves of the eclipsing cataclysmic variable SDSS J150240.98+333423.9/NZ Boo obtained in April–June, 2012 with a CCD photometer using the 60-cm telescope of the Sternberg Astronomical Institute’s Crimean station is presented (based on more than 750 images). The first observation was made ∼350–370 orbital cycles after the beginning of the outburst of April 2012; all the observations correspond to quiescence of the system. The orbital period, P = 0.0589106(4)d, changed by no more than ΔP orb/P orb ∼ 2 × 10−5 during the more than 37 200 orbital cycles since the previous observations of the system. The light curves of SDSS J150240.98+333423.9 folded with the orbital period reveal variations of the eclipse depth by up to ∼1 m , of the system’s out-of-eclipse brightness level by up to ∼0.3 m , and of the flux around the orbital hump by up to ∼0.3 m . Parameters of the system (its accretion disk, hot line, hot spot, and other components) are derived in a combined model for a cataclysmic variable that takes into account radiation from both the hot line and a hot spot on the leeward side of the gas stream. Analysis of variations of the resulting disk parameters (its radius R d , α g , temperature T in in the boundary layer) testifies to changes in these parameters between outbursts: just after the end of the outburst (1–140 orbital cycles), the disk’s radius and the temperature in its inner regions decreased and the radial temperature distribution approached that for the stationary case; after another ∼600P orb, the opposite situation was observed.