A 3-M_SUN star is seen orbiting with an unseen object with a period of 36 days and a semimajor axis of 1 AU.The mass of the unseen object is closest to A) 150 M_SUN B) 103 M_SUN C) 42 M_SUN D) 21 M_SUN E) 1 M_SUN

Question

Quizplus · Accepted Answer

Kepler's third law: P^2 = a^3/M, where P is the period, a is the semimajor axis, and M is the total mass. So, M = a^3/P^2 = (1 AU)^3/(36 days)^2 = 103 M_SUN.

A 3-MSUN Star Is Seen Orbiting with an Unseen Object

A 3-M_SUN Star Is Seen Orbiting with an Unseen Object