Objects A and B are orbiting each other. Object A has twice the mass of Object B. What can you say about their orbits?

Question

Objects A and B are orbiting each other. Object A has twice the mass of Object B. What can you say about their orbits?

A: The orbital path of Object A is smaller than the orbital path of Object B.

B: The center of Object A is the center of both orbits since A is more massive.

C: Both orbits are identical.

D: They will eventually become unbound.

E: The orbital path of Object B is smaller than the orbital path of Object A.

Answer 1

For this question your answer will be A, the orbital path is smaller than orbital path of object B.

A larger body will be still affected by the other objects presence and will orbit it , but not to same degree the smaller object will orbit it.

There are a few ways to prove this, one way that I think is the most important way to understand this is the equation for finding a barycenter of the two-body system. When using the below equation you will find that the distance of the barycenter is always closer to the larger object, so the larger object(or more massive) will orbit closer to the barycenter then the smaller object will.

d=(m/M+m)*r

m=mass of smaller body M= mass of larger body r=distance between centers of both objects