JWST sighting of decameter main-belt asteroids and view on meteorite sources
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Author(s)
Burdanov, Artem Y.
de Wit, Julien
Broz, Miroslav
Muller, Thomas G.
Hoffmann, Tobias
Ferrais, Marin
Micheli, Marco
Jehin, Emmanuel
Parrott, Daniel
Hasler, Samantha N.
Date Issued
December 9, 2024
Journal
Nature
Publisher
Springer Nature
Citation
Burdanov, A.Y., de Wit, J., Brož, M. et al. JWST sighting of decameter main-belt asteroids and view on meteorite sources. Nature (2024).
Version
Author's final manuscript
Abstract
Asteroid discoveries are essential for planetary-defense efforts aiming to prevent impacts
with Earth, including the more frequent megaton explosions from decameter impactors.
While large asteroids (≥100 km) have remained in the main belt since their formation,
small asteroids are commonly transported to the near-Earth object (NEO) population.
However, due to the lack of direct observational constraints, their size-frequency distribution —which informs our understanding of the NEOs and the delivery of meteorite
samples to Earth—varies significantly among models. Here, we report 138 detections
of the smallest asteroids (⪆10 m) ever observed in the main belt, which were enabled by JWST’s infrared capabilities covering the asteroids’ emission peaks and synthetic tracking techniques. Despite small orbital arcs, we constrain the objects’ distances and
phase angles using known asteroids as proxies, allowing us to derive sizes via radiometric
techniques. Their size-frequency distribution exhibits a break at ∼100 m (debiased cumulative slopes of q = −2.66 ± 0.60 and −0.97 ± 0.14 for diameters smaller and larger than
∼100 m, respectively), suggestive of a population driven by collisional cascade. These
asteroids were sampled from multiple asteroid families —most likely Nysa, Polana and
Massalia— according to the geometry of pointings considered here. Through additional
long-stare infrared observations, JWST is poised to serendipitously detect thousands of
decameter-scale asteroids across the sky, probing individual asteroid families and the
source regions of meteorites “in-situ”.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1038/s41586-024-08480-z
