The Dynamical Evolution of Exoplanet Systems Over Billions of Years

Exoplanet systems are expected to evolve with time as they age. In most cases though, the dynamical evolution of exoplanet systems over billion-year timescales are hard to observe. I'll describe how Galactic kinematics can provide accurate and precise age inferences for exoplanet populations and highlight the impact of those age inferences on models of planet formation and evolution. In particular, I'll show at the population level that (1) plausibly mean-motion resonant multiple-planet systems are among the youngest exoplanet systems and (2) systems with an ultra-short-period (USP) planet are among the oldest exoplanet systems. The former observation implies that convergent disk-driven Type I migration often leaves newly formed planetary systems in mean-motion resonances. The latter observation suggests that USP planets tidally migrate from their locations at the end of the planet formation process to their observed locations over several billion years.