New Light Curves and Orbital Period Investigations of the Interacting Binary System UV Piscium

Abstract

UV Psc is a typical RS CVn type system undergoing dynamic chromosphere activity. We performed photometric observations of the system in 2015 and secured new BVR light curves showing well-defined photometric waves. In this paper, we analyzed the light curves using Wilson-Devinney binary code and investigated the orbital period of the system. The combination of our light curve synthesis with the spectroscopic solution developed by previous investigators yielded the absolute parameters as: M1 = 1.104 ± 0.042 Mⵙ, R1 = 1.165 ± 0.025 Rⵙ, and L1 = 1.361 ± 0.041 Lⵙ for the primary star, and M2 = 0.809 ± 0.082 Mⵙ, R2 = 0.858 ± 0.018 Rⵙ, and L2 = 0.339 ± 0.010 Lⵙ for the secondary star. The eclipse timing diagram for accurate CCD and photoelectric timings showed that the orbital period may vary either in a downward parabolic manner or a quasi-sinusoidal pattern. If the latter is adopted as a probable pattern for the period change, a more plausible account for the cyclic variation may be the light time effect caused by a circumbinary object rather than an Applegate-mechanism occurring via variable surface magnetic field strengths.