Calculate the period T of a planet whose orbit has a semimajor axis of 25 AU

Answer 1

You can use the semi-major axis as R in Kepler's 3rd Law (it is the avg R for an elliptical orbit)

k_sunR³ = T² for all satellites of the sun. If we use earth years and astronomical units, k = 1 (because the earth has an R = 1AU and a period of 1 year)

T = sqrt(R³) in years.

Please consider a tutor.