Photometric observations and light curve solutions of the W UMa stars NSVS 2244206, NSVS 908513, CSS J004004.7+385531 and VSX J062624.4+570907

TL;DR

This study presents photometric observations and light curve analyses of four W UMa contact binary stars, revealing their overcontact configurations, spectral types, and component ratios, with some indications of additional features affecting one system.

Contribution

The paper provides new photometric data and detailed light curve solutions for four W UMa stars, highlighting their overcontact nature and component characteristics, including potential additional absorption features.

Findings

All targets are overcontact systems with fillout factors 0.15-0.26.

Components are G-K spectral types, nearly in thermal contact.

One system shows weak limb-darkening and possible extra absorption feature.

Abstract

Photometric observations in Sloan g' and i' bands of four W UMa stars, NSVS 2244206, NSVS 908513, CSS J004004.7+385531, VSX J062624.4+570907, are presented. The light curve solutions reveal that all targets have overcontact configurations with fillout factor within 0.15-0.26. Their components are of G-K spectral type and almost in thermal contacts. They are relatively close also in size and luminosity: the radius rations r_2/r_1 are within 0.75-0.90; the luminosity ratios l_2/l_1 are within 0.53-0.63. The results of the light curve solution of CSS J004007.7+385531 imply weak limb-darkening effect of its primary component and possible presence of additional absorbing feature in the system.