An exoplanet is in an elliptical orbit around a distant star. at its closest approach, the exoplanet is 0.540 au from the star and has a speed of 54.0 km/s. when the exoplanet is at its farthest distance from the star of 41.0 au, what is its speed (in km/s)? (1 au is the average distance from the earth to the sun and is equal to 1.496 ✕ 1011 m. you may assume that other planets and smaller objects in the star system exert negligible forces on the exoplanet.)