The Synthesis of Close-Binary Light Curves. III. The Hot Ellipsoidal Variables Psi Orionis and AO Cassiopelae and Evolutionary State of Six Systems

The program developed in previous papers to compute the theoretical light curves of close-binary systems, accounting for the reflection effect and distortion of both stars, is modified to include the effects of electron scattering in a hot stellar envelope. The light curves and colors of the systems 4, Ori and AO Cas (including previously unpublished observations of the former system) are used to derive the physical elements of the systems. The position of these stars (and those examined in Papers I and II) on the theoretical H-R diagram and their evolutionary states are discussed.