A study of light curve variations in eclipsing contact binary stars

Abstract

The study of light curves of W UMa (W Ursa Majoris type) eclipsing contact binary stars can provide insight into their physical dimensions as well as their evolution. By making use of different data sets, including from the All Sky Automated Survey (ASAS) and the Wide Angle Search for Planets (SuperWASP), light curves were modelled to assess if there is a trend regarding their mass-ratios q and the inclination angles i of these systems in relation to the appearance of the light curves. A selection of stars were also subjected to period variation analysis and the results thereof presented. Period changes that are fore-casted with a degree of certainty are indicative of evolutionary changes in these systems. An area of future study is to analyse amongst others the underlying causes that contribute to the variations observed. To do so requires quality data spanning decades. Results of the analysis of the appearance of light curves with regards to secondary minima in relation to q and i are presented as well as improved periods for a selection of 14 stars by making use of SuperWASP data.