Origin of the Structure of the Kuiper Belt during a Dynamical Instability in the Orbits of Uranus and Neptune

TL;DR

This paper proposes a new dynamical mechanism within the Nice model framework that explains the origin and orbital characteristics of the Kuiper belt, matching observed properties through simulations of planetary encounters and damping.

Contribution

It introduces a novel mechanism for delivering objects to the Kuiper belt during planetary instability, aligning with observed belt properties without excessive inclination excitation.

Findings

Simulations reproduce Kuiper belt's observed structure.

Neptune's eccentricity damping occurs within ~1 million years.

The mechanism explains the belt's initial emptiness and current distribution.

Abstract

We explore the origin and orbital evolution of the Kuiper belt in the framework of a recent model of the dynamical evolution of the giant planets, sometimes known as the Nice model. This model is characterized by a short, but violent, instability phase, during which the planets were on large eccentricity orbits. One characteristic of this model is that the proto-planetary disk must have been truncated at roughly 30 to 35 AU so that Neptune would stop migrating at its currently observed location. As a result, the Kuiper belt would have initially been empty. In this paper we present a new dynamical mechanism which can deliver objects from the region interior to ~35 AU to the Kuiper belt without excessive inclination excitation. Assuming that the last encounter with Uranus delivered Neptune onto a low-inclination orbit with a semi-major axis of ~27 AU and an eccentricity of ~0.3, and that subsequently Neptune's eccentricity damped in ~1 My, our simulations reproduce the main observed properties of the Kuiper belt at an unprecedented level.