The mass of the compact object in the X-ray binary her X-1/HZ Her

We have obtained the first estimates of the masses of the components of the Her X-1/HZ Her X-ray binary system taking into account non-LTE effects in the formation of the H (gamma) absorption line: m(x) = 1.8 M-circle dot and m(v) = 2.5 M-circle dot. These mass estimates were made in a Roche model based on the observed radial-velocity curve of the optical star, HZ Her. The masses for the X-ray pulsar and optical star obtained for an LTE model lie are m(x) = 0.85 +/- 0.15 M (circle dot) and m(v) = 1.87 +/- 0.13 M-circle dot. These mass estimates for the components of Her X-1/HZ Her derived from the radial-velocity curve should be considered tentative. Further mass estimates from high-precision observations of the orbital variability of the absorption profiles in a non-LTE model for the atmosphere of the optical component should be made.