Detection of Eclipses in the Cataclysmic Variable LAMOST J035913.61 + 405035.0

Abstract

I conducted photometric observations of the cataclysmic variable LAMOST J035913.61 + 405035.0 and detected eclipses. During these observations, I recorded 14 eclipses over two groups of nights separated by 13 months. I accurately determined the orbital period of the system to be $$ {P}_{\mathrm{orb}}=0.228\kern0.1em 343\kern0.1em 85\pm 0.000\kern0.1em 000\kern0.1em 21 $$ days. For the eclipses, I derived an ephemeris which is valid for a long time and suitable for studying changes in the orbital period. The out-of-eclipse magnitude of the star varied between 15.32 ± 0.02 and 17.25 ± 0.08 mag. As the brightness decreased, the eclipses became deeper and narrower. The average depth of eclipses was 1.35 ± 0.10 mag, and the average width at half-depth was 16.9 ± 0.7 min. I estimated the range of possible orbital inclinations to be between 72.8° and 76.0°, and the range of average absolute V-band magnitudes of the disc to be between 5.16 ± 0.15 and 5.44 ± 0.15 mag. Although based on the light curve from the ZTF survey, LAMOST J035913.61 + 405035.0 showed only small outbursts with amplitudes below 1.5 mag, it should be classified as a dwarf nova because the average disc brightness and mass transfer rate were below the limit of thermal instability.