Orbit of two Masses

Check this box to see masses leave trail markers:

Problem Description

Suppose you are, once again, an astronomer. This time you are observing a binary star system (two stars in orbit about one another). By carefully observing the motion of the pair of objects, you can infer the ratio of the masses. Give this a try by looking at the simulation obove.   By observing the motion of the red mass-blue mass system (feel free to "Pause" and "Step" the simulation!), estimate the ratio of the masses. Please be sure to state any assumptions you make and briefly explain the thought process you use to arrive at your estimate.