J. Escobar-Cerezo1, A. Penttilä2, T. Kohout2,3, O. Muñoz1, F. Moreno1, and K. Muinonen2,4
Astrophysical Journal 853, 71 Link to Article [DOI: 10.3847/1538-4357/aaa24d]
1Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008 Granada, Spain
2Department of Physics, P.O. Box 64, FI-00014 University of Helsinki, Finland
3Institute of Geology, The Czech Academy of Sciences, Prague, Czech Republic
4National Land Survey of Finland, Finnish Geospatial Research Institute, P.O. Box 84, FI-00521 Helsinki, Finland
Lunar soil spectra differ from pulverized lunar rocks spectra by reddening and darkening effects, and shallower absorption bands. These effects have been described in the past as a consequence of space weathering. In this work, we focus on the effects of nanophase iron (npFe0) inclusions on the experimental reflectance spectra of lunar regolith particles. The reflectance spectra are computed using SIRIS3, a code that combines ray optics with radiative-transfer modeling to simulate light scattering by different types of scatterers. The imaginary part of the refractive index as a function of wavelength of immature lunar soil is derived by comparison with the measured spectra of the corresponding material. Furthermore, the effect of adding nanophase iron inclusions on the reflectance spectra is studied. The computed spectra qualitatively reproduce the observed effects of space weathered lunar regolith.