The gravitational interaction of two planetesimals

Numerical solutions of the plane three-body problem are used to investigate the dependence on the initial data of the orbit evolution of two gravitationally interacting planetesimals, i.e., material points moving around a massive central body (i.e., the sun). The case in which the masses of the planetesimals are equal, and the case in which the mass of one of the planetesimals is considerably greater than that of the other are considered. Particular attention is given to cases when heliocentric orbits intersect during the evolution. Formulas describing particle motion around triangular libration points are obtained by an analytical study of the plane restricted circular three-body problem.