A critical review of period analyses and implications for mass exchange in W UMa Eclipsing Binaries: Paper 1

This is the first of a series of four papers, the goal of which is to identify the overcontact eclipsing binary star systems for which a solid case can be made for mass exchange. To reach this goal, it is necessary first to identify those systems for which there is a strong case for period change. We have identified 60 candidate systems; in the present paper and in two succeeding papers we will discuss the individual cases. For each system, we will present a detailed discussion and evaluation concerning the observational and interpretive material presented in the literature. An eclipse timing diagram (or diagrams), commonly referred to as an “O-C diagram”, using the latest available data will accompany each discussion. In paper 3, we will also present a table of marginal and rejected cases. In paper 4, we will present a discussion of the mechanisms that can effect period change and which of the systems presented can be reliably concluded to exhibit mass exchange.