Two stars M1 and M2 of equal mass make up a binary star system. They move in a circular orbit that has its center at the midpoint of the line that separates them. If M1 = M2 = 1.70 sm (solar mass), and the orbital period of each star is 4.45 days, find their orbital speed. (The mass of the sun is 1.99×1030 kg.) km/s