TY - JOUR
T1 - Laser Irradiation of Carbonaceous Chondrite Simulants
T2 - Space-weathering Implications for C-complex Asteroids
AU - López-Oquendo, Andy J.
AU - Loeffler, Mark
AU - Trilling, David E.
N1 - Publisher Copyright:
© 2024. The Author(s). Published by the American Astronomical Society.
PY - 2024/5/1
Y1 - 2024/5/1
N2 - Surfaces of carbonaceous asteroids (C-complex) have shown diverse, contrasting spectral variations, which may be related to space weathering. We performed laser irradiation experiments on CI and CM simulant material under vacuum to mimic the spectral alteration induced by micrometeorite impacts. We used in situ ultraviolet-visible and near-infrared reflectance spectroscopy to analyze spectral alterations in response to pulsed laser irradiation, as well as scanning electron microscopy and X-ray photoelectron spectroscopy to search for microstructural and compositional changes. Laser irradiation causes an increase in spectral slope (reddening) and a decrease in the albedo (darkening), and these changes are stronger in the ultraviolet-visible region. These spectral changes are likely driven by the excess iron found in the altered surface region although other factors, such as the observed structural changes, may also contribute. Additionally, while the 0.27 μm band appears relatively stable under laser irradiation, a broad feature at 0.6 μm rapidly disappears with laser irradiation, suggesting that space weathering may inhibit the detection of any feature in this spectral region, including the 0.7 μm band, which has typically been used an indicator of hydration. Comparing our laboratory results with optical spectrophotometry observations of C-complex asteroids, we find that the majority of objects are spectrally red and possess colors that are similar to our irradiated material rather than our fresh samples. Furthermore, we also find that “younger” and “older” C-complex families have similar colors, suggesting that the space-weathering process is near equal or faster than the time it takes to refresh the surfaces of these airless bodies.
AB - Surfaces of carbonaceous asteroids (C-complex) have shown diverse, contrasting spectral variations, which may be related to space weathering. We performed laser irradiation experiments on CI and CM simulant material under vacuum to mimic the spectral alteration induced by micrometeorite impacts. We used in situ ultraviolet-visible and near-infrared reflectance spectroscopy to analyze spectral alterations in response to pulsed laser irradiation, as well as scanning electron microscopy and X-ray photoelectron spectroscopy to search for microstructural and compositional changes. Laser irradiation causes an increase in spectral slope (reddening) and a decrease in the albedo (darkening), and these changes are stronger in the ultraviolet-visible region. These spectral changes are likely driven by the excess iron found in the altered surface region although other factors, such as the observed structural changes, may also contribute. Additionally, while the 0.27 μm band appears relatively stable under laser irradiation, a broad feature at 0.6 μm rapidly disappears with laser irradiation, suggesting that space weathering may inhibit the detection of any feature in this spectral region, including the 0.7 μm band, which has typically been used an indicator of hydration. Comparing our laboratory results with optical spectrophotometry observations of C-complex asteroids, we find that the majority of objects are spectrally red and possess colors that are similar to our irradiated material rather than our fresh samples. Furthermore, we also find that “younger” and “older” C-complex families have similar colors, suggesting that the space-weathering process is near equal or faster than the time it takes to refresh the surfaces of these airless bodies.
UR - http://www.scopus.com/inward/record.url?scp=85193821318&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85193821318&partnerID=8YFLogxK
U2 - 10.3847/PSJ/ad4028
DO - 10.3847/PSJ/ad4028
M3 - Article
AN - SCOPUS:85193821318
SN - 2632-3338
VL - 5
JO - Planetary Science Journal
JF - Planetary Science Journal
IS - 5
M1 - 117
ER -