Migration of Jupiter-family comets and resonant asteroids to near-Earth space

TL;DR

This study models the orbital evolution of Jupiter-crossing objects and resonant asteroids to estimate their collision probabilities with terrestrial planets, revealing that extinct comets significantly contribute to near-Earth object populations.

Contribution

It provides a detailed simulation-based analysis of the migration pathways of JCOs and resonant asteroids, highlighting their potential to become near-Earth objects and impact planets.

Findings

A small fraction of JCOs reach Earth-crossing orbits.

Extinct comets from the trans-Neptunian region are significant near-Earth objects.

Some objects remain in Earth-like orbits for millions of years.

Abstract

We estimated the rate of comet and asteroid collisions with the terrestrial planets by calculating the orbits of 13000 Jupiter-crossing objects (JCOs) and 1300 resonant asteroids and computing the probabilities of collisions based on random-phase approximations and the orbital elements sampled with a 500 yr step. The Bulirsh-Stoer and a symplectic orbit integrator gave similar results for orbital evolution, but sometimes give different collision probabilities with the Sun. A small fraction of former JCOs reached orbits with aphelia inside Jupiter's orbit, and some reached Apollo orbits with semi-major axes less than 2 AU, Aten orbits, and inner-Earth orbits (with aphelia less than 0.983 AU) and remained there for millions of years. Though less than 0.1% of the total, these objects were responsible for most of the collision probability of former JCOs with Earth and Venus. Some Jupiter-family comets can reach inclinations i>90 deg. We conclude that a significant fraction of near-Earth objects could be extinct comets that came from the trans-Neptunian region.