NSVS 2854398, a Short-period W UMa with Total Eclipses

We present a photometric analysis of the eclipsing variable binary star NSVS 2854398. A total of 402 images were taken in the Johnson B, V, and Cousins R band passes. All images were acquired using the Ball State University Observatory 20-inch telescope atop the Cooper Science Complex in July 2018. All images were reduced with the Image Reduction and Analysis Facility (IRAF). Differential ensemble photometry was performed using the AstroImageJ (AIJ) program. The system was modeled using the PHysics Of Eclipsing BinariEs (PHOEBE) program (v0.31a). With PHOEBE, a synthetic light curve was compared to the observed light curve to determine best-fit model parameters. Observed times of minimum light were determined and compared to a calculated time of minimum light. Model fits were improved by the addition of a single spot. Our analysis shows that NSVS 2854398 is consistent with an over-contact binary with a total eclipse and in thermal contact with a surface temperature of 4720 ± 190 K and an orbital period of 0.290 ± 0.003 days.