TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 60 (No. 1), pp. 67-74, 2008

A newly-identified spectral reflectance signature near the lunar South pole and the South Pole-Aitken Basin

Faith Vilas1, Elizabeth A. Jensen2, Deborah L. Domingue3, Lucy A. McFadden4, Cassandra J. Runyon5, and Wendell W. Mendell6

1NASA Johnson Space Center/KR, Houston, Texas 77058
2Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, California
3Applied Physics Laboratory, Johns Hopkins Road, Laurel, Maryland 20723
4University of Maryland, Department of Astronomy, College Park, Maryland 20742
5Department of Geology, College of Charleston, Charleston, South Carolina 29424
6NASA Johnson Space Center/KA, Houston, Texas 77058

(Received January 12, 2007; Revised June 17, 2007; Accepted October 6, 2007; Online published February 12, 2008)

Abstract: Signal analysis of Galileo images of the Moon suggests the presence of an absorption band centered near 0.7 μm in the reflectance spectra of areas located adjacent to the equatorward walls of lunar craters at latitudes ranging from -58 to -78° and areas contained in the South Pole-Aitken Basin. We propose three potential explanations: an Fe2+→Fe3+ charge transfer transition in oxidized iron in clinopyroxenes (high-Ca bearing pyroxenes) or phyllosilicates (Fe- and Mg-bearing sheet silicates containing adsorbed H2O and interlayer OH-), or an effect of titanium in ilmenite (a common lunar opaque material). No identification of the mineralogy is conclusive. The presence and nature of the absorption feature could be confirmed using AMICA images of the lunar far side from the Japanese mission Hayabusa, spectroscopic results from the Japanese mission Selene scheduled for launch in 2007, or the Moon Mineralology Mapper on the Indian mission Chandrayaan-1.
Key words: Moon, lunar surface composition, spectral reflectance, lunar mineralogy, lunar remote sensing.

Corresponding author E-mail: fvilas@mmto.org

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