And would the fact of the center of mass being at some point between both bodies also tend to encourage a circular orbit? Because now that I come to think of it, the visual image reminds me of how you sometimes see circular wind patterns on breezy days.
The center of mass being at some point in between is inevitable. I’m not sure how you can say that it causes anything, any more than you can say that the fact that 2+2=4 causes anything.
But there are a lot of causes of orbit circularization. Almost everything that causes orbits to do anything non-Keplerian tends to circularize orbits.
There’s not a fundamental difference between two co-orbiting bodies where the center of mass is in open space, versus the center of mass is inside the bigger body.
Earth and Moon co-orbit, and the center of mass is about 75% of the way from the center of the Earth to the surface of the Earth. So very ballpark 1000 miles below the surface and definitely inside Earth.
Conversely, the Sun & Jupiter co-orbit and the center of mass is about 107% of the way from the Sun’s center to it’s “surface”, so definitely outside the body of the Sun.
There’s no material difference between these two scenarios as to tides, circularization, etc.
Right. It’s a matter of the tidal forces (which relate to the distance between the two objects orbiting, their masses and their diameter) and the efficiency of their conversion of orbital energy to heat (which relate to elasticity (how much energy is lost during deformation).