A new method for the analysis of apsidal motions in eclipsing binaries

In this paper, a new method for the determination of apsidal motion parameters in eccentric eclipsing binaries is presented. A sequential procedure has been followed throughout allowing an automatized on-line computation of the elements and their accuracies as well as a more realistic fit to the observed times of minima. A determination of individual mean errors for the parameters of fit give us the possibility to compare the results with available theoretical models of stellar structure. In the procedure, we have introduced a determination of preliminary elements by means of Fourier transform and extended the practical equations to terms up to the fifth power of the eccentricity. An application to the well-known case of the eclipsing binary GL Car has been made. Our analysis shows an apsidal motion period of 25.3 years with a value of 0.152 for the orbital eccentricity.