Far from random: dynamical groupings among the NEO population

TL;DR

This study identifies significant dynamical groupings among near-Earth objects, revealing their origins, resonant structures, and potential links to impact events, thereby improving understanding of meteoroid impact risks.

Contribution

The paper introduces a Monte Carlo-based method to detect and analyze dynamical groupings in the NEO population, uncovering both known and new groups linked to impact events.

Findings

Recovered known groups like the Taurid Complex.

Identified new groups such as Mjolnir and Ptah.

Linked meteoroid impacts to specific NEO groupings.

Abstract

Among the near-Earth object (NEO) population there are comets and active asteroids which are sources of fragments that initially move together; in addition, some NEOs follow orbits temporarily trapped in a web of secular resonances. These facts contribute to increasing the risk of meteoroid strikes on Earth, making its proper quantification difficult. The identification and subsequent study of groups of small NEOs that appear to move in similar trajectories are necessary steps in improving our understanding of the impact risk associated with meteoroids. Here, we present results of a search for statistically significant dynamical groupings among the NEO population. Our Monte Carlo-based methodology recovers well-documented groupings like the Taurid Complex or the one resulting from the split comet 73P/Schwassmann-Wachmann 3, and new ones that may have been the source of past impacts. Among the most conspicuous are the Mjolnir and Ptah groups, perhaps the source of recent impact events like Almahata Sitta and Chelyabinsk, respectively. Meteoroid 2014 AA, that hit the Earth on 2014 January 2, could have its origin in a marginally significant grouping associated with Bennu. We find that most of the substructure present within the orbital domain of the NEOs is of resonant nature, probably induced by secular resonances and the Kozai mechanism that confine these objects into specific paths with well-defined perihelia.