Asteroids Impacting the Solar System Planets and the Moon. III. Real Impacts from Known Objects and LSST Discovery Predictions
Abstract
Impact rates predicted using pre-impact source-population models and those inferred from observations disagree by a factor of a few to ∼200 across the Solar System planets and the Moon. An exciting opportunity for an additional observational constraint is the discovery of asteroids before impact and their tracking until impact. We evaluate this prospect based on both known objects and forecasts of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). First, we identify impacts from known objects, confirming multiple past cases and predicting two coming impacts: 2015 FK488, a ∼1.8 km Centaur whose nominal orbit predicts an impact with Jupiter in ∼200 yr, and 2022 KG1, a <10 m NEO recently removed from the impact-risk lists but whose nominal trajectory leads to an Earth impact in ∼260 yr. Both orbits are poorly constrained. Second, assuming the model-based impact rate, we predict that LSST will discover 7 of the 59 synthetic impactors quantified in our previous analysis. All of the discovered impactors will impact Jupiter, and they have a size range of ∼200−2000 m and expected discovery-to-collision lead times of $1.94-257.4$ yr. Two of them are discovered inside Jupiter's Hill sphere, offering rare opportunities to observe the transition from a temporary bound orbit to impact before it happens. If instead we assume the observation-inferred impact rates, LSST will at most discover ∼20 future Earth impactors (>10 m) and ∼300 future Jupiter impactors (>10 m), with a wider range on both ends for discovery-to-collision lead times. These results demonstrate that LSST can identify a subset of planetary impactors years to centuries before collision, providing a new observational pathway for testing source-population models and the impact-rate mismatch.
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BibTeX
@misc{cheng2026asteroids,
title = {{Asteroids Impacting the Solar System Planets and the Moon. III. Real Impacts from Known Objects and LSST Discovery Predictions}},
author = {Qifeng Cheng and Daniel Scolnic},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.22045},
eprint = {2609.22045},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22045},
}
RIS
TY - UNPB
TI - Asteroids Impacting the Solar System Planets and the Moon. III. Real Impacts from Known Objects and LSST Discovery Predictions
AU - Qifeng Cheng
AU - Daniel Scolnic
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.22045
UR - https://arxiv.org/abs/2609.22045
AB - Impact rates predicted using pre-impact source-population models and those inferred from observations disagree by a factor of a few to ∼200 across the Solar System planets and the Moon. An exciting opportunity for an additional observational constraint is the discovery of asteroids before impact and their tracking until impact. We evaluate this prospect based on both known objects and forecasts of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). First, we identify impacts from known objects, confirming multiple past cases and predicting two coming impacts: 2015 FK488, a ∼1.8 km Centaur whose nominal orbit predicts an impact with Jupiter in ∼200 yr, and 2022 KG1, a <10 m NEO recently removed from the impact-risk lists but whose nominal trajectory leads to an Earth impact in ∼260 yr. Both orbits are poorly constrained. Second, assuming the model-based impact rate, we predict that LSST will discover 7 of the 59 synthetic impactors quantified in our previous analysis. All of the discovered impactors will impact Jupiter, and they have a size range of ∼200−2000 m and expected discovery-to-collision lead times of $1.94-257.4$ yr. Two of them are discovered inside Jupiter's Hill sphere, offering rare opportunities to observe the transition from a temporary bound orbit to impact before it happens. If instead we assume the observation-inferred impact rates, LSST will at most discover ∼20 future Earth impactors (>10 m) and ∼300 future Jupiter impactors (>10 m), with a wider range on both ends for discovery-to-collision lead times. These results demonstrate that LSST can identify a subset of planetary impactors years to centuries before collision, providing a new observational pathway for testing source-population models and the impact-rate mismatch.
ER -