As the default simulation played out beautifully on-load, I immediately started to question: "hang on, I thought there wasn't a solution for 3 bodies, but this looks stable".
Before I could complete the thought, it fell apart magnificently :)
These are meta-stable, in that only a perfect initial state (positions and velocities) will be stable. Even then, I expect quantum uncertainties would kick in at some point. (In the simulator, the default system goes unstable at about 500 seconds, probably due to the limits of floating point math.)
>probably due to the limits of floating point math
It's due to the integration scheme (2nd order, albeit symplectic) and time step (5e-4, ok if better scheme is used).
There are quite a few solutions ;)
https://www.sciencealert.com/we-just-got-12000-new-solutions...
The default configuration is a special case. They are all in a stable orbit around the common barycenter, always forming an equilateral triangle. We actually have closed form solutions for this kind of configuration.
See https://en.wikipedia.org/wiki/Three-body_problem#General_sol...
PS: The site has more stable presets under load preset.