Two stars in a binary system orbit around their center of mass. The centers of the two stars are 7.78x1011 m apart. The larger of the two stars has a mass of 4.19x1030 kg, and its center is 1.75x1011 m from the system's center of mass. What is the mass of the smaller star?

Answer 1

m=M/10^30

4.19*1.75 = m*(7.78-1.75) = m * 6.03
so
m = 1.22
so
m = 1.22 * 10^30 kg