Deterministic and Stochastic: Period Variations of Eclipsing Binaries

The differences between observed and calculated ephemeris eclipse times (O - C ) can reveal variations in the periods of eclipsing binaries, and therefore can be a tool to investigate the evolving behavior of these systems. Many potential causes include apsidal motion, perturbations by a third body, and magnetic torques. Depending on the cause, the variations can be stochastic or deterministic, or a combination. In this study we examine some methods to probe whether O–C period variations are chaotic deterministic, periodic deterministic, or stochastic.