A Laboratory Spectroscopic, Photometric, and Polarimetric Dataset of Three Ordinary Chondrites, Including the Recent Maoming Fall: Grain-size and Simulated Space-weathering Effects
- 1China University of Geosciences
Abstract
We present a coordinated laboratory optical data set for three equilibrated ordinary chondrites (OCs; LL5/6, L6, and H6), including the recently witnessed Maoming fall of 2025 May 28, to investigate the coupled effects of grain size, surface structure, and simulated space weathering on their spectral, photometric, and polarimetric properties. Intact slabs and three grain-size fractions were measured in the fresh state and after two levels of pulsed-laser irradiation using Fourier-transform infrared reflectance spectroscopy, bidirectional reflectance distribution function (BRDF) measurements, and polarization phase curves. Irradiation generally produces spectral darkening, reddening, and weakening of the 1 and 2 μ m absorption bands, although the degree of reddening depends on both composition and grain size. BRDF measurements reveal a systematic transition from nearly isotropic scattering in fine powders to enhanced backscattering in coarse powders and pronounced specular reflection from slabs. These scattering characteristics remain largely unchanged after irradiation, indicating that grain size and surface structure exert stronger control on angular scattering than irradiation-induced optical darkening. The specular component is strongly suppressed in the irradiated LL5/6 slab but remains evident in the L6 and especially H6 slabs, suggesting a contribution from metal-rich phases. Polarimetric measurements further show systematic differences between slabs and powders, with surface morphology influencing both the negative-polarization branch and the large-phase-angle polarization behavior. This dataset demonstrates that grain size and surface structure are as important as composition and space weathering in governing the optical properties of OCs, providing complementary constraints for interpreting OC-like asteroid surfaces.
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BibTeX
@article{wei2026laboratory,
title = {{A Laboratory Spectroscopic, Photometric, and Polarimetric Dataset of Three Ordinary Chondrites, Including the Recent Maoming Fall: Grain-size and Simulated Space-weathering Effects}},
author = {Zichen Wei and Hao Zhang},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/aea69a},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aea69a},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A Laboratory Spectroscopic, Photometric, and Polarimetric Dataset of Three Ordinary Chondrites, Including the Recent Maoming Fall: Grain-size and Simulated Space-weathering Effects
AU - Zichen Wei
AU - Hao Zhang
PY - 2026
DA - 2026/10/08
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aea69a
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aea69a
AB - We present a coordinated laboratory optical data set for three equilibrated ordinary chondrites (OCs; LL5/6, L6, and H6), including the recently witnessed Maoming fall of 2025 May 28, to investigate the coupled effects of grain size, surface structure, and simulated space weathering on their spectral, photometric, and polarimetric properties. Intact slabs and three grain-size fractions were measured in the fresh state and after two levels of pulsed-laser irradiation using Fourier-transform infrared reflectance spectroscopy, bidirectional reflectance distribution function (BRDF) measurements, and polarization phase curves. Irradiation generally produces spectral darkening, reddening, and weakening of the 1 and 2 μ m absorption bands, although the degree of reddening depends on both composition and grain size. BRDF measurements reveal a systematic transition from nearly isotropic scattering in fine powders to enhanced backscattering in coarse powders and pronounced specular reflection from slabs. These scattering characteristics remain largely unchanged after irradiation, indicating that grain size and surface structure exert stronger control on angular scattering than irradiation-induced optical darkening. The specular component is strongly suppressed in the irradiated LL5/6 slab but remains evident in the L6 and especially H6 slabs, suggesting a contribution from metal-rich phases. Polarimetric measurements further show systematic differences between slabs and powders, with surface morphology influencing both the negative-polarization branch and the large-phase-angle polarization behavior. This dataset demonstrates that grain size and surface structure are as important as composition and space weathering in governing the optical properties of OCs, providing complementary constraints for interpreting OC-like asteroid surfaces.
SN - 0004-637X
SN - 1538-4357
ER -