What info (measurements) do you need to determine the mass of each star in a binary pair?

What information (measurements) do you need to determine the mass of each star in a binary pair? Explain how you would use the information to determine the massesWhat info (measurements) do you need to determine the mass of each star in a binary pair?Since mass can be determined only from gravitational attraction, and the only stars (with the exception of the Sun, and gravitationally-lensed stars), for which this can be determined are binary stars, these are a uniquely important class of stars. In the case of a visual binary star, after the orbit has been determined and the stellar parallax of the system determined, the combined mass of the two stars may be obtained by a direct application of the Keplerian harmonic law.