Scott Kenyon's N-Body Code


	*N-body Code for Planet Formation*

	N-Body codes calculate orbits of planets around a star Accurate gravity field Perturbations due to close passes Objects merge when they collide N-Body codes have several advantages Calculate evolution of large planets accurately Can treat gas accretion and migration more accurately Derive orbits of large planets Derive final planet masses N-Body codes also have some disadvantages Cannot calculate evolution of planetesimals (too many orbits to follow) No interaction with leftover planetesimals No predictions for dust production Our approach: Encke method Inertial coordinate frame follows Keplerian orbit Friends-of-friends for nearest neighbors Hierarchical treatment of timesteps Force-evaluations calculated directly Treecode backup for large numbers of particles Input drag from interactions with gas & small bodies Input accretion from planetesimal swarm Accuracy is machine precision for orbits O(N²) for force-solver Code has been extensively tested Code reproduces previous calculations		We used the n-body code to calculate the evolution of icy planets after a stellar encounter. Learn more ...