Origin of orbits of secondaries in the discovered trans-Neptunian binaries

TL;DR

This paper investigates the orbital characteristics of secondary bodies in trans-Neptunian binaries, analyzing how their inclinations depend on various orbital and physical parameters, and interprets these findings through a collision-based formation model.

Contribution

It introduces a collision model of formation for trans-Neptunian binary systems that explains observed orbital inclinations and angular momentum distributions.

Findings

Approximately 40% of trans-Neptunian binaries have negative angular momentum.

Orbital inclinations depend on distance, eccentricity, and size ratios.

The collision model aligns with observational data.

Abstract

The dependences of inclinations of orbits of secondaries in the discovered trans-Neptunian binaries on the distance between the primary and the secondary, on the eccentricity of orbits of the secondary around the primary, on the ratio of diameters of the secondary and the primary, and on the elements of heliocentric orbits of these binaries are studied. These dependences are interpreted using the model of formation of a satellite system in a collision of two rarefied condensations composed of dust and/or objects less than 1 m in diameter. It is assumed in this model that a satellite system forms in the process of compression of a condensation produced in such a collision. The model of formation of a satellite system in a collision of two condensations agrees with the results of observations: according to observational data, approximately 40% of trans-Neptunian binaries have a negative angular momentum relative to their centers of mass.