Features of the Dynamical Evolution of a Massive Disk of Trans-Neptunian Objects

TL;DR

This study models the dynamical evolution of a massive trans-Neptunian disk, revealing how gravitational interactions influence orbital eccentricities and the survival of distant small bodies over billions of years.

Contribution

It provides new insights into how a massive disk's self-gravity and planetary perturbations shape the orbital distribution of trans-Neptunian objects over Solar system timescales.

Findings

Eccentricities of objects tend to increase due to secular gravitational effects.

Higher initial disk mass leads to fewer surviving objects in the observable region.

Most objects maintain or decrease their eccentricities, remaining beyond 100 AU.

Abstract

Dynamical features of a massive disk of distant trans-Neptunian objects are considered in the model of the formation of small bodies in the Hill region of a giant gas-dust clump that arose as a result of gravitational instability and fragmentation of the protoplanetary disk. The dynamical evolution of orbits of small bodies under the action of gravitational perturbations from the outer planets and self-gravity of the disk has been studied for a time interval of the order of a billion years. It is shown that the secular effects of the gravitational action of a massive disk of small bodies lead to an increase in the eccentricities of the orbits of individual objects. The result of this dynamical behavior is the creation of a flux of small bodies coming close to the orbit of Neptune. The change in the number of objects surviving in the observable region of distant trans-Neptunian objects (the region of orbits with perihelion distances of 40 < q < 80 AU and semimajor axes 150 < a < 1000 AU), over time depends on the initial mass of the disk. For disks with masses exceeding several Earth masses, there is a tendency to a decrease in the number of distant trans-Neptunian objects surviving in the observable region after evolution for a time interval of the order of the age of the Solar system, with an increase in the initial mass. On the other hand, for most objects, orbital eccentricities decrease under the influence of the self-gravity of the disk. Therefore, the main part of the disk remains in the region of heliocentric distances exceeding 100 AU.