| Autor: |
Magaña, L. O.1,2,3 (AUTHOR) lizeth.magana@jhuapl.edu, Retherford, K. D.1,2 (AUTHOR), Byron, B. D.4 (AUTHOR), Hendrix, A. R.5 (AUTHOR), Grava, C.2 (AUTHOR), Mandt, K. E.3,6 (AUTHOR), Raut, U.1,2 (AUTHOR), Czajka, E.1,2 (AUTHOR), Hayne, P. O.7 (AUTHOR), Hurley, D. M.3 (AUTHOR), Gladstone, G. R.1,2 (AUTHOR), Poston, M. J.2 (AUTHOR), Greathouse, T. K.2 (AUTHOR), Pryor, W.8 (AUTHOR), Cahill, J. T.3 (AUTHOR), Stickle, A.3 (AUTHOR) |
| Předmět: |
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| Zdroj: |
Journal of Geophysical Research. Planets. Aug2023, Vol. 128 Issue 8, p1-16. 16p. |
| Abstrakt: |
Nighttime Lyman Alpha Mapping Project (LAMP) observations are used to investigate condensed volatiles at the south polar region of the Moon. This study incorporates LAMP data from the first ∼7 years of the mission and Diviner annual maximum temperatures to search for volatile signatures associated with H2O, NH3, and CO2. Other stable potential species, for example, SO2 and H2S, are not identifiable with the ultraviolet ratio‐temperature techniques and are not directly addressed in this study. We confidently detect a ∼20% increase in normalized Off‐band (175–190 nm) to On‐band (148–162 nm) albedo ratios (consistent with condensed surface volatiles) at temperatures below ∼115 K. Elevated normalized ratios extend to temperatures capable of supporting pure aforementioned ices over geologically long time scales. Although ∼115 K is consistent with H2O lifetimes of ∼1‐Myr, the presence of CO2 and NH3 are not uniquely delineated by the data trends with temperature. Future spectral modeling to appropriately identify the composition and abundance of these condensed volatiles remains necessary. Normalized albedo ratios are further analyzed for candidate species via maximum temperatures to inform the likelihood of ice signatures: H2O (70 K < T ≤ 115 K), NH3 + H2O (60 K < T ≤ 70 K), and CO2 + NH3 + H2O (T ≤ 60 K). We compare normalized albedo ratios across seven regions of interest (ROI), including Faustini, Shoemaker, Haworth, Cabeus, Amundsen, Nobile, and an unnamed region. Such comparisons allow for characterization of relative abundances of volatiles across the ROI important for their utilization in future crewed and robotic missions to the Moon. Plain Language Summary: Spectra taken by the Lyman Alpha Mapping Project ultraviolet spectrograph and surface temperature inferred from the Diviner radiometer (both onboard the Lunar Reconnaissance Orbiter) are used to investigate the presence of ices within craters at the Moon's south pole. We analyze spectral features at temperatures where H2O, NH3, and CO2 ice are stable. We find signatures consistent with condensed surface volatiles at temperatures below the H2O ice stability temperature, but are unable to confidently delineate NH3 and CO2 signatures. We further find that normalized signatures can be used to estimate the relative abundance of ice species across regions of interest. Volatile studies, such as the one presented here, are important for resource utilization in future crewed and robotic missions to the Moon. Key Points: Cold traps may support volatile reserves, which may be useful for resource utilization and for determining the origin of lunar volatilesAn increase in volatile signatures where H2O is thermodynamically stable is found; CO2, and NH3 are not confidently delineatedNormalized albedo differences provide insight on relative volatile species abundances between cold traps of interest [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
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