Commensurabilities between ETNOs: a Monte Carlo survey

TL;DR

This study systematically investigates commensurabilities among ETNOs using Monte Carlo methods, revealing patterns similar to those in known belts and supporting the hypothesis of undetected trans-Plutonian planets like Planet Nine.

Contribution

It introduces a Monte Carlo survey of ETNO commensurabilities, providing evidence for gravitational influences of hypothetical distant planets.

Findings

Patterns resemble those in main and trans-Neptunian belts

Some commensurabilities align with the Planet Nine hypothesis

Objects may be in 5:3 and 3:1 resonances with a planet at 700 au

Abstract

Many asteroids in the main and trans-Neptunian belts are trapped in mean motion resonances with Jupiter and Neptune, respectively. As a side effect, they experience accidental commensurabilities among themselves. These commensurabilities define characteristic patterns that can be used to trace the source of the observed resonant behaviour. Here, we explore systematically the existence of commensurabilities between the known ETNOs using their heliocentric and barycentric semimajor axes, their uncertainties, and Monte Carlo techniques. We find that the commensurability patterns present in the known ETNO population resemble those found in the main and trans-Neptunian belts. Although based on small number statistics, such patterns can only be properly explained if most, if not all, of the known ETNOs are subjected to the resonant gravitational perturbations of yet undetected trans-Plutonian planets. We show explicitly that some of the statistically significant commensurabilities are compatible with the Planet Nine hypothesis; in particular, a number of objects may be trapped in the 5:3 and 3:1 mean motion resonances with a putative Planet Nine with semimajor axis of about 700 au.