1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I found out the distance between the star and companion which I calculated as 1.11x1010m (Ignoring the mass of the companion).Then I calculated the radius of the stars orbit, using r = vt/2∏ since vt = circumference. It turned out as1.4x108m. Then I simply found the radius of the companions orbit which was 1.096x1010m. I then used r2 = m1(m1) + m2 x d and then manipulated it to make m2 the subject. But my answer came out as 5.47x1027kg. Which I assume is wrong since it's supposed to be much less than the mass of the star.