Not to nit pick but the earth orbits the center of gravity of the solar system. (Somewhere between the center and surface of the sun)
In constant radius along a 2D plane?
I’m pretty sure it all depends on your point of reference. If you take it that the stationary point is the center of gravity of earth’s solar system, I believe you are correct. However, if you use the earth’s center of gravity as your reference, then everything changes. Its all relative...
Brainiac Teabagger! Let’s beat him up!