  Calculations carried out to model the evolution of HDE 226868, under
different assumptions about the stellar wind mass loss rate, provide robust
limits on the present mass of the star. It has to be in the range 40 +- 5 solar
masses if the distance to the system is in the range 1.95 to 2.35 kpc and the
effective temperature of HDE 226868 in the range 30000 to 31000 K. Extending
the possible intervals of these parameters to 1.8 to 2.35 kpc and 28000 to
32000 K, one gets for the mass of the star the range 40 +- 10 solar masses.
Including into the analysis observational properties such as the profiles of
the emission lines, rotational broadening of the absorption lines and the
ellipsoidal light variations, one can estimate also the mass of the compact
component. It has to be in the ranges 20 +- 5 solar masses and 13.5 to 29 solar
masses for the cases described above. The same analysis (using the evolutionary
models and the observational properties listed above) yields lower limit to the
distance to the system of about 2.0 kpc, if the effective temperature of HDE
226868 is higher than 30000 K. This limit to the distance does not depend on
any photometric or astrometric considerations.
