Estimating the Mass of the Companion Star
The star in question can be determined by its spectral classification
to be a type OB supergiant. Using various measurements of distance,
luminosity, and interstellar reddening, its mass can be reasonably
determined. The absolute lower limit, which is what we are interested
in for determining the lowest possible mass of the visible companion
is about 9 solar masses. Further research has established that it is
more likely around 30 solar masses.