Aplanet with the mass mp = 2 x 1026 kg orbits a massive star with mass 10 times the solar mass. at perihelion, it has a speed of 1.4 x 103 m/s and is 1.0 x 1015 m from the star. the orbital radius increases to 2.77 x 1015 m at aphelion. note: ms = 2 x 1030 kg a) what is the planet’s speed at aphelion? b) what is the period of the orbit? c) what is the energy of the orbit?