AAVSO: American Association of Variable Star Observers

BVI Observations of the Eclipsing Binary XZ Andromedae at the EKU Observatory

Volume 50 number 1 (2022)

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Marco Ciocca
Department of Physics, Geosciences, and Astronomy, Eastern Kentucky University, Richmond, KY 40475; marco.ciocca@eku.edu


The eclipsing binary XZ Andromedae has been the subject of many observing campaigns, due to variability of its orbital period and the interesting mechanisms causing the change. We therefore observed this star during the period October–November 2021. We determined the current orbital period (P = 1.357308 (18) d), and using transformed standard BVI magnitudes, constructed a model of the eclipsing binary using the PHOEBE (Physics of Eclipsing Binaries) and Binary Maker 3 software packages to compare with results from previous studies. The model that best fit the data suggests that XZ And is a semidetached system with the secondary filling the Roche Lobe. The parameters fit of the primary (T1 = 9393 K, mass M1 = 2.1 solar masses, and radius R1 = 2.2 solar radii) are indicative of a A1V main sequence star, while the secondary’s parameters (T2 = 5334, M2 = 1.02, and R2 = 2.40) point to a star in a more advanced evolutionary status.