This is a movie of the evolving color-magnitude diagram from the N-body model of the old open cluster NGC 188. Binaries are plotted with blue points, and show the combined light of the unresolved system. Single stars are plotted in black points. The dynamical and stellar evolution calculations were performed using NBODY6, with some modifications to define the binary population and output format.
Credit: Movie by Aaron Geller using IDL and MPEG Streamclip; dynamical and stellar evolution calculations performed with NBODY6 / Funding: NSF