An investigation of the tidally driven period changes in detached binary systems through O-C time series analysis: the case of RT And and WY Cnc †

Detached binary systems are subjected to a variety of physical mechanisms which are able to change their period in a continuous way and in a broad band of timescales. Assuming that these changes should be detectable in O–C diagrams in a way specified by the physical theory of the underlying mechanisms, we carry out a preliminary study in a properly selected sample of detached binaries, where no mass transfer is expected. We are primarily interested in finding traces of tidal moments in observed orbital period changes (possibly coupled with stellar wind angular momentum losses). We focus our attempts on two short-period chromospherically active binaries (RT And and WY Cnc), whose expected period changes rates are found to be close to those derived by means of time series analysis. Emphasis is also given to systems which show a remarkably constant orbital period, in disagreement with the values expected by theory. †This paper was originally due to be published in the Special Issue: Close Binary Stars in Mod...