Precision Analyses Of The Totally Eclipsing, Solar Type Binary, V1115 Cassiopeiae And Its Third Component

CCD, BVRI light curves of V1115 CAS were taken on 8, 9, and 10, November 2020, remotely, at the SARA Jacobus Kapteyn 1.0-m Telescope , La Palma, Canary Islands, Spain. Further observations were made in October 2020 at Dark Sky Observatory. The variability of V1115Cas (2MASS J01322075+5513569) was discovered by Hoffmeister (1966). It is classified as a contact variable with a mean V magnitude of 14.32, an amplitude of V=0.532 mags and a period of 0.32328248d. Four times of minimum light were determined from our present observations, which include two primary and two secondary eclipses. We selected 8 times of low light from ASAS SN observations and 48 timings from the literature. From these we determined the following linear ephemeris, JD Hel MinI = 24558870.5185(17)d + 0.32328248(15)×E (1). In the 19 year period study, the residuals form a sinusoidal curve. An analysis of this curve yields a third body of mass 0.23 solar masses. A Wilson-Devinney analysis reveals that the system is an W-type W UMa binary with a somewhat extreme mass ratio, q = 0.2296 ± 0.0002 (star 1 is the more massive, primary component, 1/q = M1/M2 = 4.4). Its Roche Lobe fill-out is ~24%. Two spots were needed in the solution. The temperature difference of the components is ~225 K, with the more massive component as the slightly cooler one, so that in the present observations, it is an W-type W UMa Binary. The inclination is high, 86.06 ± 0.13° resulting in a total eclipse. As a result, the secondary minimum has a time of constant light with an eclipse duration of some 37 minutes. More information is given in this preliminary report.