Presentation #400.04 in the session Multiple Stars Systems and Cataclysmic Variables.
CCD, BVRI light curves V509 Cam were taken on UT 23, October and 21-24, November, 2022, at the Dark Sky Observatory, Appalachian State University with the 32” reflector, by Dan Caton. The variability of V509 Cam was discovered By S. Yoshida of the MISAO project (Mis V1375). ASASSN classifies as an EW contact variable with a V magnitude range of 14.2-14.8 with a period of 0.3929885 days. Six times of low light were found in ASAS observations. One time of minimum light was found in VSX. Our present observations, included three primary eclipses and three secondary eclipses. From these data, we determined the following linear and quadratic ephemerides,
JD Hel MinI = 2459907.9921 ± 0.0013d + 0.392987592 ± 0.0000054×E (1)
JD Hel MinI = 2459907.98988 ± 0.00056d + 0.39298400 ± 0.00000032×E -0.0000000000056 ± 0.000000000005×E2 (2).
Thus, from a brief 6-year period study including one timing 69 years previous, the period is found to be decreasing, or the mass ratio is approaching 1.00 (q=M2/M1). A Wilson-Devinney analyses approximates that the system is a W-type W UMa. Its Roche Lobe fill-out is only ~4% so it is very slightly overcontact. One cool spot was needed in the solution. The temperature difference of the components is only ~37 K, with the more massive component possibly as the slightly cooler one. The inclination is 73.1±0.1˚ and the mass ratio is near one so no total eclipse is possible. A q-search shows that the mass ratio of the actual solution which can be found from a radial velocity study done with a large telescope (>0.4-m) probably varies between 0.4 and 1.1 (If q<1, the system is an A-type W UMa). No third light was indicated. More information is given in this preliminary report.