On the dynamical evolution of Scattered Disk Objects outside the planetary system

TL;DR

This study uses long-term dynamical simulations to analyze the evolution of fictitious Scattered Disk Objects, emphasizing the role of resonances and external objects in transferring objects into the inner Oort Cloud.

Contribution

It provides new estimates on the efficiency of transferring objects from the Scattered Disk to the Oort Cloud, confirming the significance of external perturbers.

Findings

Resonant effects influence orbital evolution.

Transfer efficiency to the Oort Cloud is higher than previously estimated.

External objects with perihelia beyond Neptune are key in feeding the Oort Cloud.

Abstract

We report the results of dynamical simulations, covering Gyr timescales, of fictitious Scattered Disk Objects as a follow-up to an earlier study by Fern\'andez et al. (2004: {\it Icarus} {\bf 172}, 372). Our dynamical model is similar in that it does not include external agents like passing stars or the Galactic tide. Only the four giant planets are explicitly treated as perturbers. We analyze the random-walk behaviour of the inverse semi-major axis by means of a simplified circular restricted 3-body problem as an approximate analogue. Our results concerning the role of resonant effects and the transfer efficiency into the orbital energy domain of the inner Oort Cloud are in broad agreement with the earlier papers, and we confirm the important role of external objects (with perihelia beyond Neptune's orbit) in feeding the Oort Cloud. We estimate the efficiency of this transfer to be even somewhat higher than previously found.