Architecture and Dynamics of Planetary Systems

The Kepler mission represents a breakthrough in the dynamics of exoplanetary systems.  Over 500 systems with multiple transiting planets have been found.  By comparing transit durations of planets in the same system, we can see that inclinations of planets relative to each other are on the order of 2 degrees, just like in the Solar System.  The number of systems with detectably perturbed orbits is now over 100.  Models of the systems with high signal-to-noise transit timing variations (TTVs) can uniquely determine the mass and orbital parameters of the perturbing planet.  In one exceptional system, four planets have apparently migrated into a chain of orbital period resonances.  Destabilization of planetary systems near their star, resulting in giant impacts among the planets, can form new systems that match the orbital properties of the bulk of the systems that we see.  We are continuing to monitor the TTVs in these systems to obtain mass-radius measurements for cool exoplanets and inferences on the formation and evolution of exoplanetary systems.