Light curve solutions of six eclipsing binaries at the lower limit of periods of the W UMa stars

TL;DR

This study presents photometric observations and light curve solutions for six short-period eclipsing binaries near the lower period limit of W UMa stars, including three newly discovered systems, revealing their contact nature and component characteristics.

Contribution

It provides detailed light curve analyses of six short-period binaries, adding new systems to the W UMa family and exploring their physical parameters and surface phenomena.

Findings

All targets are contact or overcontact binaries.

Four systems have equal-sized components with near-equal mass ratios.

Five systems show O'Connell effect explained by cool spots.

Abstract

Photometric observations in V and I bands of six eclipsing binaries at the lower limit of the orbital periods of W UMa stars are presented. Three of them are newly discovered eclipsing systems. The light curve solutions revealed that all short-period targets were contact or overcontact binaries and added new six binaries to the family of short-period systems with estimated parameters. Four binaries have equal in size components and mass ratio near 1. The phase variability of the V-I colors of all targets may be explained by lower temperatures of their back surfaces than those of their side surfaces. Five systems revealed O'Connell effect that was reproduced by cool spots on the side surfaces of their primary components. The light curves of V1067 Her in 2011 and 2012 were fitted by diametrically opposite spots. The applying of the criteria for subdivision of the W UMa stars to our targets led to ambiguous results.