The First Light Curve Solutions of GW Leo and Period Study of Two Contact Binary Systems

TL;DR

This study presents the first light curve analysis of GW Leo and updates the period of QT Boo, revealing period decreases and detailed system parameters for these contact binaries.

Contribution

It provides the first light curve solutions for GW Leo and a new ephemeris for QT Boo, including period change rates and system characteristics, enhancing understanding of these contact binaries.

Findings

GW Leo is a contact W UMa binary with a mass ratio of 0.881

Both systems show decreasing periods, indicating mass transfer or angular momentum loss

Distance to GW Leo is estimated at approximately 466 parsecs

Abstract

We performed the first light curve analysis of GW Leo and a new ephemeris is obtained for QT Boo. In the present photometric study of two contact binary systems, we found that the period of these binary systems is decreasing at a rate of dp/dt=-6.21*10^(-3) days yr^(-1) for GW Leo, and dp/dt=-4.72*10^(-3) days yr^(-1) for QT Boo, respectively. The light curve investigation also yields that the system GW Leo is a contact W UMa eclipsing binary with a photometric mass ratio of q=0.881+-0.030, a fillout factor of f=3%, and an inclination of 54.060+-0.066 deg. Due to the O'Connell effect which is known as asymmetries in the light curves' maxima, a cold spot is employed along with the solution. We also calculate the distance of GW Leo from the distance modulus formula as 465.58+-23 pc, which is relatively close to the quantity measured by the Gaia DR2 using the binary systems' parallax. Moreover, the positions of their components on the H-R diagram are represented.