For the mathematically minded ...
The total mass of the system M = 4*pi^2*r^3 / (G*T^2)
For the derivation look here ...
http://outreach.atnf.csiro.au/educat...nary_mass.html
From Table 1 (see Craig's Post 3 below),
T = 309.673 days = 309.673*24*3600 s
r = 389.4 * radius of Sun = 389.4*6.96*10^8 metres
G = gravitational constant = 6.673*10^-11 m^3/kg/s^2
Mass of Sun = 1.989*10^30 kg
Substituting, gives M = 1.64488*10^31 kg ~ 8.27 * Sun.
Data indicates the two star's masses are equal,
so each star has mass 8.27/2 ~ 4.14 * Sun
Regards, Rob