A binary star system has a period of 7.7E6 (7700000 s). It is noted that one star is moving twice as fast as the other star. a) If the semi major axis of their "orbit" is a=10^11 m, what is the mass of each star? b). what is the semi-major axis of the orbit traced out by the more massive star? c). If the eccentricity e=0.4, what is their closest approach to each other.