VIS-IR Spectroscopy of Mixtures of Water Ice, Organic Matter, and Opaque Mineral in Support of Small Body Remote Sensing Observations

Visual-to-infrared (VIS-IR) remote sensing observations of different classes outer solar system objects indicate the presence water ice and organics. Here, we present laboratory reflectance spectra in 0.5–4.2 μm spectral range binary particulate mixtures ice, organics analogue (kerite), an opaque iron sulphide phase (pyrrhotite) to investigate effects varying mixing ratios, endmember grain size, modality. The are also compared implementations Hapke model (Hapke, 2012). We find that minor amounts (≲1 wt%) kerite (investigated sizes 45–63 <25 μm) can remain undetected when mixed coarse-grained (67 ± 31 suggesting similar meteoritic insoluble organic matter (IOM) might be characterized by larger detectability thresholds. Additionally, our measurements VIS absolute ice-containing is not necessarily monotonically linked abundance. latter better constrained indicators such as band depths VIS-IR diagnostic absorptions slopes. Simulation intimate with a semi-empirical formulation suggests simplistic assumptions on size distribution shape may lead estimated ratios considerably offset from nominal values. Finally, grains fine-grained pyrrhotite inclusions (intraparticle mixture) have been positively modified version Lucey Riner (2011).