The eclipsing precataclysmic binary RR Caeli

Photometric and some spectroscopic observations of the white dwarf-red dwarf binary RR Cae (V = 14.36 mag) are presented. The light curve confirms an earlier report of deep eclipses. An orbital period of 0.303695 days is derived. Small out-of-eclipse variations-at least partly explicable as the result of reflection and tidal distortion-and a weak secondary eclipse are also detected. The phase of the latter suggests an eccentric orbit that, however, has yet to be confirmed. The H alpha absorption line of the white dwarf contains a narrow emission core. Otherwise, the red spectrum is dominated by absorption structures of a very late (similar to M6) main-sequence star. Eclipse simulations permit a unique solution for the orbital inclination and the component radii in units of their separation. This, in turn, leads to a self-consistent solution for the absolute values of numerous system parameters, the most important of which are the masses estimated by using theoretical and empirical mass-radius relationships (M-1 = 0.365 M-.; M-2 = 0.089 M-.). A photometric parallax of 12 pc is derived. The future evolution of this precataclysmic binary is briefly discussed.