Statistical study of semi-detached and near contact semi-detached binaries

Abstract We carried out a statistical study of 107 semi-detached with combined light curve solutions. 1. We derived an empirical period-dependent mass-radius relation, thereby revealing the impossibility of having evolved semi-detached systems with very short periods. 2. Statistically, the near-contact semi-detached systems have the common properties of nearly equal mass densities of the components, larger mass-ratios, shorter periods and smaller specific angular momenta and their A- F-type secondaries generally have greater densities than the secondaries of classical Algol systems of the same spectral types. A detailed discussion is also made in this paper on the evolution of near-contact semi-detached binaries.