Two planets of equal mass orbit a much more massive star (figure). Planet m1 moves in a circular orbit of radius 1×108 km with period 2 year. Planet m2 moves in an elliptical orbit with closest distance r1=1×108 km and farthest distance r21.8×108km, as shown. Using the fact that mean radius of an elliptical orbit is the length of the semi-major axis, find the period of m′2 s orbit.