Tracing the main belt origins of S-complex near-Earth objects: From space mission targets to meteorite sources
5 affiliations
- 1Aix-Marseille University, CNRS, CNES, LAM, Institut Origines
- 2European Southern Observatory (ESO)
- 3Charles University, Faculty of Mathematics and Physics, Institute of Astronomy
- 4Department of Earth, Atmospheric and Planetary Sciences, MIT
- 5Department of Astronomy and Planetary Science, Northern Arizona University
Abstract
Context. Space missions to near-Earth objects (NEOs) provide remarkable opportunities to study and characterise their physical and compositional properties in detail. Interpreting these results in a broader context requires knowledge of their provenance, and therefore of their source family in the main asteroid belt.
Aims. In this work, we aim to identify the family sources of six S-complex NEOs visited or soon to be visited by space missions. A secondary objective is to investigate the size-dependent orbital behaviour of the broader S-complex NEO population using the MITHNEOS spectroscopic dataset.
Methods. We combine two complementary approaches: near-infrared spectral fitting of NEO spectra with ordinary chondrite (OC) analogues reddened by an empirical space-weathering model, using reduced χ ² minimisation, and cross-validation with probabilistic dynamical maps of the main NEO source families.
Results. We identify the closest OC type and the most probable source family of the six targets: LL6–7 chondrites and the Flora family for Eros, Itokawa, Apophis, and Torifune; LL3 chondrites and the Nysa family for Toutatis; L chondrites and the Massalia family for Didymos-Dimorphos. When in situ observations are available (Itokawa and Eros), the classifications are consistent. Applied to the broader S-complex NEO population dataset, the spectral classification and orbital properties distributions are broadly consistent with dynamical simulation models. When accounting for observational biases, we find that at small diameters (≤100 m), the fractions of H-and L-type objects increase at the expense of LL6–7 types, with their low-inclination orbital properties being consistent with origins in the Massalia (L) and Koronis (H) families.
Conclusions. Combining spectral fitting with OC analogues and dynamical probability maps provides a robust method of identifying the source families of individual NEOs. Below D ∼100 m, the compositional distribution of S-complex NEOs begins to approach that of meteorite falls. This represents direct observational evidence, based on spectroscopic measurements of S-complex NEOs, of the emergence of the source regions of OC meteorites.
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BibTeX
@article{simon2026tracing,
title = {{Tracing the main belt origins of S-complex near-Earth objects: From space mission targets to meteorite sources}},
author = {P. N. Simon and P. Vernazza and M. Marsset and M. Brož and R. P. Binzel and F. DeMeo and C. A. Thomas and L. Jorda},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = oct,
doi = {10.1051/0004-6361/202661440},
url = {https://www.aanda.org/10.1051/0004-6361/202661440},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Tracing the main belt origins of S-complex near-Earth objects: From space mission targets to meteorite sources
AU - P. N. Simon
AU - P. Vernazza
AU - M. Marsset
AU - M. Brož
AU - R. P. Binzel
AU - F. DeMeo
AU - C. A. Thomas
AU - L. Jorda
PY - 2026
DA - 2026/10/27
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202661440
UR - https://www.aanda.org/10.1051/0004-6361/202661440
AB - Context. Space missions to near-Earth objects (NEOs) provide remarkable opportunities to study and characterise their physical and compositional properties in detail. Interpreting these results in a broader context requires knowledge of their provenance, and therefore of their source family in the main asteroid belt. Aims. In this work, we aim to identify the family sources of six S-complex NEOs visited or soon to be visited by space missions. A secondary objective is to investigate the size-dependent orbital behaviour of the broader S-complex NEO population using the MITHNEOS spectroscopic dataset. Methods. We combine two complementary approaches: near-infrared spectral fitting of NEO spectra with ordinary chondrite (OC) analogues reddened by an empirical space-weathering model, using reduced χ ² minimisation, and cross-validation with probabilistic dynamical maps of the main NEO source families. Results. We identify the closest OC type and the most probable source family of the six targets: LL6–7 chondrites and the Flora family for Eros, Itokawa, Apophis, and Torifune; LL3 chondrites and the Nysa family for Toutatis; L chondrites and the Massalia family for Didymos-Dimorphos. When in situ observations are available (Itokawa and Eros), the classifications are consistent. Applied to the broader S-complex NEO population dataset, the spectral classification and orbital properties distributions are broadly consistent with dynamical simulation models. When accounting for observational biases, we find that at small diameters (≤100 m), the fractions of H-and L-type objects increase at the expense of LL6–7 types, with their low-inclination orbital properties being consistent with origins in the Massalia (L) and Koronis (H) families. Conclusions. Combining spectral fitting with OC analogues and dynamical probability maps provides a robust method of identifying the source families of individual NEOs. Below D ∼100 m, the compositional distribution of S-complex NEOs begins to approach that of meteorite falls. This represents direct observational evidence, based on spectroscopic measurements of S-complex NEOs, of the emergence of the source regions of OC meteorites.
SN - 0004-6361
SN - 1432-0746
ER -