Fourier analysis of the light curves of eclipsing variables. XXIII

The method of evaluating the photometric perturbations Bsub(2m) of eclipsing variables in the frequency domain, developed by Kopal for an interpretation of mutual eclipses in systems whose components are distorted by axial rotation and mutual tidal action. The aim of the present paper has been to establish explicit expressions for the photometric perturbation Bsub(2m) in such systems, regardless of the kind of eclipses and non-integral values of m. Recently, Kopal introduced two different kinds of integrals with respect to associated α-functions and I-integrals which have been expressed in terms of certain general types of series that can be easily programmed for automatic computation within seconds of real time on high-speed computers. Following a brief introduction in which the need of this new approach will be expounded, an integral is deduced which should make it possible to evaluate explicit expressions for fsup((h))sub(*), fsup((h))sub(1), fsup((h))sub(2) as well as Bsub(2m). (Auth.)