Asteroids Impacting the Solar System Planets and the Moon. I. Collision Rates from N-body Simulations
Abstract
Previous studies have shown a mismatch between the simulated rate of asteroids impacting the Earth and the observed rate, posing an important problem for planetary defense. Extending this analysis to other planets offers a new opportunity to examine minor body populations and impactor models. We present a unified simulation framework that estimates intrinsic D≳10~m impactor rates on the eight planets and the Moon. We construct size-calibrated source populations of Near Earth Objects (NEOs), Main Belt Asteroids (MBAs), Jupiter-family comets (JFCs), Centaurs, and scattering trans-Neptunian objects (TNOs), and propagate them with a 300-year N-body simulation. To avoid relying on black-box-like collision flags, we identify close encounters and estimate impact rates in two complementary ways: a direct count of realized impactors from object-level minimum-distance calculation and a collision expectation based on population-level impact parameter statistics. We predict over 300 years there will be 6.0+3.8−2.7 impactors on Venus (all NEOs), 10.0+11.3−4.9 on Earth (NEOs and JFCs), ∼2981+481−469 on Jupiter (mainly MBAs and JFCs), 1228+2759−1017 on Saturn (mainly Centaurs), and none on the remaining planets with the 1σ upper limits spanning <1.8 (inner planets) to <1×108 (outer planets; weak constraint). Jupiter uniquely receives both fast unbound impactors (>50 km s−1) and slower bound ones reaching down to ∼20 km s−1. In a companion paper, we compare our predictions with observations and test whether the gap extends across the Solar System and whether current telescopes can observe these collisions.
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BibTeX
@misc{cheng2026asteroids,
title = {{Asteroids Impacting the Solar System Planets and the Moon. I. Collision Rates from N-body Simulations}},
author = {Qifeng Cheng and Daniel Scolnic},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.22042},
eprint = {2609.22042},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22042},
}
RIS
TY - UNPB
TI - Asteroids Impacting the Solar System Planets and the Moon. I. Collision Rates from N-body Simulations
AU - Qifeng Cheng
AU - Daniel Scolnic
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.22042
UR - https://arxiv.org/abs/2609.22042
AB - Previous studies have shown a mismatch between the simulated rate of asteroids impacting the Earth and the observed rate, posing an important problem for planetary defense. Extending this analysis to other planets offers a new opportunity to examine minor body populations and impactor models. We present a unified simulation framework that estimates intrinsic D≳10~m impactor rates on the eight planets and the Moon. We construct size-calibrated source populations of Near Earth Objects (NEOs), Main Belt Asteroids (MBAs), Jupiter-family comets (JFCs), Centaurs, and scattering trans-Neptunian objects (TNOs), and propagate them with a 300-year N-body simulation. To avoid relying on black-box-like collision flags, we identify close encounters and estimate impact rates in two complementary ways: a direct count of realized impactors from object-level minimum-distance calculation and a collision expectation based on population-level impact parameter statistics. We predict over 300 years there will be 6.0^+3.8_−2.7 impactors on Venus (all NEOs), 10.0^+11.3_−4.9 on Earth (NEOs and JFCs), ∼2981^+481_−469 on Jupiter (mainly MBAs and JFCs), 1228^+2759_−1017 on Saturn (mainly Centaurs), and none on the remaining planets with the 1σ upper limits spanning <1.8 (inner planets) to <1×10^8 (outer planets; weak constraint). Jupiter uniquely receives both fast unbound impactors (>50 km s^−1) and slower bound ones reaching down to ∼20 km s^−1. In a companion paper, we compare our predictions with observations and test whether the gap extends across the Solar System and whether current telescopes can observe these collisions.
ER -