| The first search for multiple periodic structure of a major subset of the RS CVn class of interacting binary stars systems, using a rigorous numerical approach appropriate to unevenly-spaced gapped data, is presented. The main intent of this dissertation is to characterize properly the power spectral content of RS CVn binary light curves and describe how this information can constrain the current models for the systems. If the light curve can be considered as a tracer of stellar surface activity, then the photometric distortions can be used to characterize magnetic activity cycles and add to the understanding of stellar dynamics.; The data set for this dissertation is provided by the Fairborn Observatory from the first two years of observing with the first generation Automatic Photoelectric Telescope (APT). Thirty-six RS CVn systems were observed in the Johnson UBV filter system down to a statistical noise level of {dollar}sim{dollar}0{dollar}sp{lcub}rm m{rcub}01{dollar}. An interactive analysis environment, for the 8086/80286/80386 based workstations, is described that was specifically developed in order to analyze the volumes of time-serial data generated by the APT.; Most of the systems exhibit multiple periodic structure, 40% of which show changes in the photometric period on a time scale of a few hundred days. A preference is observed for photometric periods with time scales near the orbital and half orbital periods. The effect is particularly strong for the shorter period systems and is interpreted as evidence for synchronous, or near synchronous, rotation.; A strong linear correlation in the periods for the multiply periodic systems is observed which indicates a preferential pairing of spot groups on the stellar surface. No correlation is found for the relative phases of the multiple periodic signals.; Changes in the photometric period are associated with variations in the amplitude of the distortion wave, which would indicate the growth and decay of spot groups. The growth and decay of pairs of spot groups, arbitrarily separated in phase, on a differentially rotating star is the model most consistent with the results of my analysis. High resolution, long term observations are needed to properly address the details of differential rotations. |
