1. The problem statement, all variables and given/known data A certain binary star system consists of two stars of masses m and 3m respectively separated by a distance of 1.5 * 10^12 m measured between their centres. These stars revolve in sync with each other around their common centre of mass. If the smaller star has a mass of 1.0 * 10^30 kg, what is their common period of revolution? r = 1.5 * 10^12 m m1 = 1.0*10^30 kg m2 = 3.0*10^30 kg 2. Relevant equations Fg = Gmm/r^2 Fc = 4mpi^2r/T^2 3. The attempt at a solution Initially, I thought I could do Fc = Fg and solve for period, but I'm not sure if that's the right way to do it and it doesn't sound right either.