First photometric investigations of three eclipsing binaries: AST19571, AST21541, and AST38503

Abstract AST3-1 is the second-generation optical photometric telescope at Dome A in Antarctica. In this study, photometric solutions of three eclipsing binaries comprising AST19571, AST21541, and AST38503 were determined for the first time using the light curves obtained with AST3-1. The light curves for the three binaries in the Galactic disk field were analyzed with the Wilson–Devinney method. We found that AST19571 and AST21541 are intermediate-contact binary systems with fill-out factors of f = 39.9 ( ± 5.4 ) % and 36.4( ± 4.7) %, respectively, and their mass ratios were determined as q = 0.275 ( ± 0.0034 ) and 0.25( ± 0.0024). AST38503 was shown to be a deep-contact binary system with a degree of contact of f = 66 ( ± 33 ) % and a mass ratio of q = 0.314 ( ± 0.03 ) . Some light minimum times were derived for the three contact binary stars. The results showed that the period of AST19571 is increasing at a rate of d p / d t = + 4.71 × 10 − 7 . This increase in the period could be explained by mass transfer between the components. The absolute parameters were estimated for the components of the three binaries.