Can the orbital distribution of Neptune's 3:2 meanmotion resonance result from stability sculpting?
Abstract
We explore a simplified model of the outcome of an early outer Solar System gravitational upheaval during which objects were captured into Neptune's 3:2 meanmotion resonance via scattering rather than smooth planetary migration. We use Nbody simulations containing the sun, the four giant planets, and test particles in the 3:2 resonance to determine whether longterm stability sculpting over 4.5 Gyr can reproduce the observed 3:2 resonant population from an initially randomly scattered 3:2 population. After passing our simulated 3:2 resonant objects through a survey simulator, we find that the semimajor axis (a) and eccentricity (e) distributions are consistent with the observational data (assuming an absolute magnitude distribution constrained by prior studies), suggesting that these could be a result of stability sculpting. However, the inclination (i) distribution cannot be produced by stability sculpting and thus must result from a distinct process that excited the inclinations. Our simulations modestly underpredict the number of objects with highlibration amplitudes (A_{ϕ}), possibly because we do not model transient sticking. Finally, our model underpopulates the Kozai subresonance compared to both observations and to smooth migration models. Future work is needed to determine whether smooth migration occurring as Neptune's eccentricity damped to its current value can resolve this discrepancy.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 September 2023
 DOI:
 10.1093/mnras/stad2026
 arXiv:
 arXiv:2307.06280
 Bibcode:
 2023MNRAS.524.3039B
 Keywords:

 Kuiper belt: general;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 15 pages, 13 figures