Presentation #202.05 in the session Dynamics Beyond Neptune.
The observed populations of transneptunian objects (TNOs) in Neptune’s mean motion resonances provide important clues about the nature and extent of giant planet migration in our solar system’s early history. To test scenarios for the dynamical histories of the giant planets, we rely on numerical simulations that approximate different migration histories for the planets and track how test particles representing primordial TNOs end up distributed once the giant planets arrive at their final locations. But there remains a question not satisfactorily answered in the current literature: how closely do the end states of the simulated giant planets’ orbits need to resemble the orbits of the real, present day giant planets for the simulation to produce acceptably consistent predictions to compare to the real, observed TNO distributions. Modelers typically impose some range in giant planet period ratios and eccentricity ranges in deciding whether a migration simulation output is “acceptable”, but how to define this acceptability has not actually been examined in much detail, even in the simplest case of smooth outward giant planet migration. We will present a suite of smooth planet migration simulations that result in final giant planet orbits with varying levels of fidelity to the current giant planets in terms of orbital period ratios, eccentricity and inclination ranges, and dominant eccentricity and inclination secular modes. By examining the detailed distribution of resonant particles captured in these simulations via resonance sweeping, we can determine which aspects of the final giant planet system architecture are most important to match in migration simulations. We focus on resonance sweeping because it is a very efficient capture mechanism, allowing us to explore a wide range of planet architectures with a large number of captured test particles at relatively modest computational cost. The lessons learned from these simulations can then guide future explorations of the less-efficient resonant capture mechanisms in the more complicated giant planet migration scenarios that are needed to reproduce many of the observed features of the TNO population.
This work is supported by NASA Emerging Worlds grant 80NSSC21K0376.