TY - JOUR
T1 - Spectral effects of regolith porosity in the Mid-IR – Pyroxene
AU - Martin, A. C.
AU - Emery, J. P.
AU - Loeffler, M. J.
N1 - Funding Information:
The authors would like to thank Sean Lindsay, Daniel Britt, Will Grundy, and Carey Lisse for invaluable discussions regarding the inception, and methodology of this work, and Molly McCanta and Allan Patchen for their guidance with electron microprobe sample preparation. Additional thanks goes to the National Museum of Natural History (NMNH) for lending their B06-045 to our study. We would also like to acknowledge that this work was primarily done in Northern Arizona, at the base of the San Francisco Peaks, on homelands sacred to Native Americans through the region. Additional work was done in Eastern Tennessee, on the traditional land of the Tsalagi and Tsoyaha people. This work is supported by the National Aeronautics and Space Administration's Science Mission Directorate Research and Analysis Solar System Workings programNH19ZDA001N.
Funding Information:
The authors would like to thank Sean Lindsay, Daniel Britt, Will Grundy, and Carey Lisse for invaluable discussions regarding the inception, and methodology of this work, and Molly McCanta and Allan Patchen for their guidance with electron microprobe sample preparation. Additional thanks goes to the National Museum of Natural History (NMNH) for lending their B06-045 to our study. We would also like to acknowledge that this work was primarily done in Northern Arizona, at the base of the San Francisco Peaks, on homelands sacred to Native Americans through the region. Additional work was done in Eastern Tennessee, on the traditional land of the Tsalagi and Tsoyaha people. This work is supported by the National Aeronautics and Space Administration's Science Mission Directorate Research and Analysis Solar System Workings program NH19ZDA001N .
Publisher Copyright:
© 2023 The Authors
PY - 2023/6
Y1 - 2023/6
N2 - The regolith porosity on airless bodies in the Solar System has a known effect on remotely acquired spectra in the mid-infrared (MIR; 5–35 μm). Previous experiments quantifying this effect have focused on olivines. Here we report systematic laboratory experiments designed to quantify the effect of regolith porosity on the MIR spectra of pyroxene, an important rock forming mineral on Earth, the Moon, and throughout the Solar System. Specifically, we have measured MIR spectra of eight natural pyroxene minerals and mixtures over three particle size fractions (< 20 μm, 20–45 μm, and 45–63 μm) with varying degrees of porosity. Our results indicate that 0% regolith porosity spectra are dominated by surface scattering, 90% regolith porosity spectra are dominated by volume scattering, and the transition between the two regimes is gradual. Comparing selected spectra to the Trojan asteroid (624) Hektor, we estimate the regolith porosity of its surface to be >80%, and that the surface contains a significant fraction of amorphous material. Overall, these results are quite similar to our previous olivine findings, supporting the conclusion that regolith porosity strongly affects the shape and subsequent interpretation of MIR spectra of silicate-rich surfaces.
AB - The regolith porosity on airless bodies in the Solar System has a known effect on remotely acquired spectra in the mid-infrared (MIR; 5–35 μm). Previous experiments quantifying this effect have focused on olivines. Here we report systematic laboratory experiments designed to quantify the effect of regolith porosity on the MIR spectra of pyroxene, an important rock forming mineral on Earth, the Moon, and throughout the Solar System. Specifically, we have measured MIR spectra of eight natural pyroxene minerals and mixtures over three particle size fractions (< 20 μm, 20–45 μm, and 45–63 μm) with varying degrees of porosity. Our results indicate that 0% regolith porosity spectra are dominated by surface scattering, 90% regolith porosity spectra are dominated by volume scattering, and the transition between the two regimes is gradual. Comparing selected spectra to the Trojan asteroid (624) Hektor, we estimate the regolith porosity of its surface to be >80%, and that the surface contains a significant fraction of amorphous material. Overall, these results are quite similar to our previous olivine findings, supporting the conclusion that regolith porosity strongly affects the shape and subsequent interpretation of MIR spectra of silicate-rich surfaces.
KW - Experimental techniques
KW - Infrared observations
KW - Regolith
KW - Spectroscopy
KW - Trojan asteroids
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U2 - 10.1016/j.icarus.2023.115507
DO - 10.1016/j.icarus.2023.115507
M3 - Article
AN - SCOPUS:85150079136
SN - 0019-1035
VL - 397
JO - Icarus
JF - Icarus
M1 - 115507
ER -