We present a new study of the eclipsing cataclysmic variable SDSS J154453.60+255348.8 to determine the object’s nature and its system parameters together with the probe of the accretion flow structure in the system. Based on analyses of new simultaneous time-resolved photometric and spectroscopic observations of SDSS J154453.60+255348.8 and using our light-curve modeling techniques and the Doppler tomography method, we found that the system contains a white dwarf with the mass of MWD = 0.62(7) M⊙ and an evolved red dwarf as a secondary. The system inclination is close to 90 deg and the mass ratio is q = 0.49(2). The secondary has an effective temperature T2 = 3 400(40) K and a radius about 1.35(15) times larger than a zero-age main sequence star with similar mass. From observation of the system in high and low brightness states, we conclude that SDSS J154453.60+255348.8 is a long orbital period VY Scl-type system. The accretion disk in the high state is about two times less than the truncation radius, and is completely missing during the low state of the system.

No abstract