The apsidal motion test of stellar structure in relativistic systems

We have compared observational data of apsidal motion rates for relativistic eclipsing binaries with theoretical predictions based on stellar theoretical models. Ten double-lined eclipsing binaries with high quality light curves and radial velocities were selected. The analysis of the data available indicate that the predictions by the General Relativity and the new stellar models are able to explain the shift in the periastron position. The two versions of the non-symmetrical theory of gravitation were also investigated. The early version of this theory (1984) is not supported when contrasted with recent observational data since it predicts too slow apsidal motion rates. The more recent version (1989) presents several problems in its formulation, like too many degrees of freedom and some parameters for which there is no severe physical constraint. Moreover, such a theory is not able to predict a priori the apsidal motion rates.