From mean motion resonances to scattered planets: Producing the solar system, eccentric exoplanets, and late heavy bombardments

We show that interaction with a gas disk may produce young planetary systems with closely spaced orbits, stabilized by mean motion resonances between neighbors. On longer timescales, after the gas is gone, interaction with a remnant planetesimal disk tends to pull these configurations apart, eventually inducing dynamical instability. We find that this can lead to a variety of outcomes; some cases resemble the solar system, while others end up with high-eccentricity orbits reminiscent of the observed exoplanets. A similar mechanism has been previously suggested as the cause of the lunar late heavy bombardment. Thus, it may be that a large-scale dynamical instability, with more or less cataclysmic results, is an evolutionary step common to many planetary systems, including our own.