Keeping one star from spiraling towards another star that is pinned in place?

[smjjames]

I'm thinking of messing around with planet formation with the Alpha Centauri system and I'm not sure whether I want to pin Alpha Centauri a into place while A Centauri b orbits. Planets don't seem to have too much of an issue though. However, the thing is that when I pin it in place, Centauri b just slowly spirals to it's doom. Letting them move around like normal lets it work fine.

I may or may not remove Proxima Centauri and if I do leave it in, I won't do planet formation around it since the habitable zone is so close in that the timestep would be too slow for my preferences.

Also, I haven't tried to work with binary star systems yet, so I don't know about doing planet formation and stuff around them. I have messed with very close binaries, but not with planet formation or even more separated binaries like Alpha Centauri A and B.

[FiahOwl]

Why do you want one pinned?? Doesn't that take away some of the binary systems basic mechanics?

[smjjames]

I just want to keep the system from moving around too much, and yeah you're right, it would take away from the basic mechanics because the gravitational momentum (or whatever) isn't being shared between the two objects around the center of mass.

Planets don't seem to have as much of an issue though, probably because the center of mass is inside the star anyways. Even then, theres still the stellar wobble.

I could try putting them an equidistant position from grid location 0,0,0.