Interpretation of the light curves of eclipsing binaries with disklike envelopes. The HZ Herculis system

A method is proposed for restoring the structure of the accretion disk in a binary system from analysis of eclipse curves. Application of the method to the x-ray binary HZ Herculis yields the distribution of brightness and color temperatures over the optical accretion disk associated with the neutron star. The luminosity, mean temperature, and size of the disk are correlated with the phase of the 35-day cycle of x-ray variability. The empirical parameters derived for the accretion disk agree with the theory of disk accretion onto relativistic objects.