If You Found an Exoplanet Whose Mass Was the Same

Multiple Choice

If you found an exoplanet whose mass was the same as Jupiter's, but the planet orbited its star with a period of 2 years and a semimajor axis of 1 AU, what would be the mass of its star? For reference, Jupiter has a semimajor axis of 5.4 AU and an orbital period of 12 years.

A) 0.25 M_Sun
B) 0.5 M_Sun
C) 2.0 M_Sun
D) 1.5 M_Sun
E) 4.0 M_Sun