Constraints on Planetary Migration that Explain Structure in the Kuiper Belt

The current distributions of trans-Neptunian objects (TNOs) in mean motion resonance (MMR) are directly connected to the gravitational sculpting they experienced during the epoch of giant planet migration. Several theories for planetary migration exist, but none have been able to reproduce the entire structure of the Solar System. In this poster, we report two migration scenarios that alone could explain some structure in the 3:2 MMR and help constrain upper limits for a timescale and distance during Neptune’s outward migration. For the first scenario — gravitational upheaval —a large amount of computing power is necessary to model a wide enough range of planet-planet scattering directly, so it is a difficult problem to solve. We take a simplified approach by studying the stability sculpting of the 3:2 MMR after a large scattering event such as the well-known Nice Model. In this scenario, non-resonant particles are shaved away over time while the resonant particles remain stable for billions of years. Our model is able to produce non-rejectable distributions for semi-major axis and eccentricity when compared to the Outer Solar System Origins Survey. For the second scenario — planetesimal-driven migration — we investigate the migration of Neptune. We simulate various planetesimal-planet interactions to solve for missing normalization factors in a previously derived analytical model for the random walk of a planet produced by the interactions with a disk of planetesimals. Noise due to planetesimal-driven migration is recognized across various migration models, but a general constraint taking into account weaker resonances is still needed. Weaker resonances have a harder time retaining objects in resonance, so they are a great tool for our case study. We use the current observed size distribution of the Kuiper Belt to find a maximum constraint on the amount of mass in large objects during any epoch of Neptune’s planetesimal driven migration. These results provide constraints on the more complicated migration scenarios needed to explain the Kuiper Belt.