There is a special class of binary stars called W UMa binary stars, in which both stars are similar to each other and closely orbit around their common center of gravity. Their orbits can be so close that their outer atmospheres can come into contact with each other. This article describes observations of six eclipsing binary stars that are identified as W UMa type cases. The results of this study can add to the base of knowledge astronomers have about W UMa binary stars.

http://www.raa-journal.org/raa/index.php/raa/article/view/2059