Binary asteroids in mean-motion resonances

TL;DR

This study investigates the relationship between binary asteroids and mean-motion resonances across different regions, revealing that resonances may influence binary formation and evolution, with 82 new resonant binary asteroids identified.

Contribution

It introduces a resonance identification algorithm applied to over 700 asteroids, discovering 82 new resonant binary systems and analyzing their distribution across regions.

Findings

Over 30% of trans-Neptunian objects are in MMRs with long libration times.

Main-belt asteroid pairs show 10-12% resonance occurrence.

Over 17% of NEOs are in transient resonances.

Abstract

The purpose of this study is to investigate the relation between binary asteroids and mean motion resonances (MMRs). For more than 700 asteroids from two catalogues, the Johnston Archive [Johnston, 2024] and the Gaia DR3 VizieR list of binary candidates from Liberato et al. [2024], we applied a resonance identification algorithm, treating all planetary perturbations. Our results showed that the presence of binary asteroids in MMRs largely depends on their dynamical class. The highest percentage, more than 30%, is found in the Trans- Neptunian region, where most of these objects have exhibited resonant librations longer than 10 Myr. For the main-belt asteroid pairs, this percentage is about 10-12%. Contrary to expectations, the more unstable region populated with NEOs, showed a higher percentage of resonant pairs (above 17%), but with temporal resonant captures. These results could indicate that the mean motion resonances, particularly the stronger ones, could play a role in the evolution and formation of binary systems. Finally, we highlight that in the present paper, 82 resonant binary asteroids are newly identified.