Two planets orbit a distant star. one planet has a semi-major axis of 10 au and a period of 10 years. the second planet has an orbit which is highly eccentric. at closest approach (called periastron) it is 1 au from the star, while its maximum distance from the star (called apastron) is 19 au. draw, approximately to scale, the orbits of the two stars about the parent star. what is the orbital period of the second planet?