The eclipsing pre-cataclysmic binary RR Caeli

Albert Bruch & Marcos P. Diaz

Laboratório Nacional de Astrofísica, Itajubá, Brazil

Abstract:

Photometric and some spectroscopic observations of the white dwarf - red dwarf binary RR Cae (V= 14 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 - explicable at least partly as due to reflection and tital distortion - and a weak secondary eclipse are also detected. The phase of the latter suggests an excentric orbit which, however, has still to be confirmed. The H absorption line of the white dwarf contains a narrow emission core. Otherwise, the red spectrum is dominated by absorption structures of a very late (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_solar; M_2 = 0.089 M_solar). A photometric parallax of 12 pc is derived. The future evolution of this pre-cataclysmic binary is briefly discussed.

Stars: variables: other - Stars: binaries: eclipsing - Stars: individual: RR Cae

 

• Introduction
• Observations
• Eclipse timings and ephemeris
• Analysis of the light curve
  • The primary eclipse
  • The out-of-eclipse variations
  • The secondary eclipse
  • Eclipse simulations
• The spectrum
• Discussion
  • Component radii and masses
  • Luminosity and distance
  • Radial velocities
  • Reflection effect, tidal variations and secondary eclipse
  • Evolutionary considerations
• Conclusions
• Bibliography
• About this document ...