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

Keywords methods: data analysis — catalogs — stars: fundamental parameters — stars: binaries: eclipsing: individual (1SWASP J173828.46+111150.2, 1SWASP J174310.98+432709.6 ≡ V1067 Her, NSVS 11534299, NSVS 10971359, NSVS 11234970, NSVS 11504202)

https://doi.org/10.1088/1674–4527/15/9/006