Talk:Multiple star

"Barycentre" versus "Centre of Mass"
Spacepotato. In your updates you have changed all the written "centre of mass" back to "barycentre".

I should point out that "barycentre" usually refers to the the balance point between the two mass, which in the solar system lies inside the larger mass bodies. It is used to refer the solar system objects, and in such terms as "barycentric co-ordinates" or "barycentric dynamical time" (See The Penguin Dictionary of Astronomy by Jacqueline Mitton etc.)

In Norton's Star Atlas glossary, for example, it refers that this applies to binary stars as well, but the U.N. Naval and HMNO ephemeris refer that this applies only in the Solar System. Both The Binary Stars (Aitken) and Double Stars (Heintz), specify "centre of mass".)

In my experience, I have always used "centre of mass" to describe double stars, binaries and multiple stars to distinguish between the two terms - this applying to stars. It makes sense to do so, because the balance point unlike every situation (except perhaps Pluto and Charon)  have the balance point inside the bodies.

I think this should be changed. Comment please.

Arianewiki1 (talk) 05:26, 20 August 2008 (UTC)
 * The two terms mean the same thing. Whether the barycenter is inside or outside one of the bodies in the system, you may use either barycenter or center of mass. Spacepotato (talk) 09:00, 20 August 2008 (UTC)

Trapezia: ..The centre of gravity is not fixed at some point but moves as the stars change their mutual positions.

Moves with respect to what, pray? All motion is relative after all.