The Bulletin of The Korean Astronomical Society (천문학회보)

The Korean Astronomical Society (한국천문학회)
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Color Ratios of Parallel-Component Polarization as a Maturity Indicator for the Lunar Regolith

  • Kim, Sungsoo S. (Kyung Hee University, Dept. of Astronomy and Space Science) ;
  • Jung, Minsup (Kyung Hee University, Dept. of Astronomy and Space Science) ;
  • Sim, Chae Kyung (Kyung Hee University, Dept. of Astronomy and Space Science) ;
  • Kim, Il-Hoon (Kyung Hee University, Dept. of Astronomy and Space Science) ;
  • Park, So-Myoung (Kyung Hee University, Dept. of Astronomy and Space Science) ;
  • Jin, Ho (Kyung Hee University, Dept. of Astronomy and Space Science)
  • Published : 2015.04.10
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Abstract

Polarization of the light reflected off the Moon provides information on the size and composition of the particles in the lunar regolith. The mean particle size of the regolith can be estimated from the combination of the albedo and degree of polarization, while the color ratio of the parallel-component polarization (CP) has been suggested to be related to the amount of nanophase metallic iron (npFe^0) inside the regolith particles. Both the mean size and npFe^0 abundance of the particles have been used as maturity indicators of the regolith since sustained impacts of high energy particles and micro-meteoroids cause comminution of particles and production of npFe^0. Based on our multispectral polarimetric observations of the whole near side of the Moon in the U, B, V, R, and I bands, we compare the maps of the mean particle size, CP, and the optical maturity (OM). We find that the mean particle size map is sensitive to the most immature (~0.1 Gyr) soil, the OP map to the intermediate immaturity (a few 0.1 Gyr) soil, and the CP map to the least immature (~1 Gyr) soil.

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