A photometric study of two neglected eclipsing binaries

TL;DR

This study provides the first detailed photometric and period analysis of two neglected eclipsing binaries, revealing their configurations and mass transfer activities.

Contribution

It introduces new photometric data and analysis for V1321 Cyg and CR Tau, including the use of the ELISa code for light curve modeling.

Findings

V1321 Cyg is a close detached system with a low mass ratio.

CR Tau is a semi-detached system with ongoing mass transfer.

CR Tau shows a long-term period increase.

Abstract

We present the first BVR photometry, period variation, and photometric light-curve analysis of two poorly studied eclipsing binaries V1321 Cyg and CR Tau. Observations were carried out from November 2017 to January 2020 at the observatory of Uzhhorod National University. Period variations were studied using all available early published as well as our minima times. We have used newly developed ELISa code for the light curve analysis and determination of photometric parameters of both systems. We found that V1321 Cyg is a close detached eclipsing system with a low photometric mass ratio of $q=0.28$ which suggests that the binary is a post mass transfer system. No significant period changes in this system are detected. CR Tau is, on the other hand, a semi-detached system where the secondary component almost fills its Roche lobe. We detected a long-term period increase at a rate of $1.49 \times 10^{-7} d/y$, which support mass transfer from lower mass secondary component to the more massive primary.