Calculate the period T of a planet whose orbit has a semimajor axis of 2.9 AU.

Question

Answer should be in years.

Answer 1

IF this planet orbits a star with same mass as our Sun, then T² (yr) = r³ (AU) = (2.9)³ = 24.4 and T = 4.9 years.

ELSE, r³ / T² ≅ M_* / M_Sun.