CCD Photometry, Light Curve Modeling,and Period Study of the Overcontact Binary Systems NSVS 7245866 and V685 Pegasi

摘要

Precise time-series multi-color (B, V,and I_c) light curve data were acquired at UnderOak Observatory (UO) from NSVS 7245866 (2017) and V685 Peg (2016). Prior to this investigation only monochromatic CCD data for both variables were available from automated surveys which employ sparse sampling strategies. Each target produced new times-of-minimum from data acquired at UO as well as values extrapolated from the SuperWASP survey. These results along with other eclipse timings from the literature were used to generate new ephemerides. Roche modeling of the observed light curve data was accomplished using the Wilson-Devinney code. Each system exhibits a total eclipse, therefore a reliable photometrically derived value for the mass ratio (q_(ptm)) was determined which consequently provided initial estimates for the physical and geometric elements of both variable systems.