Visible and near-infrared reflectance of hyperfine and hyperporous particulate surfaces

The composition of Solar System surfaces can be inferred through reflectance and emission spectroscopy, by comparing these observations to laboratory measurements radiative transfer models. While several populations objects appear covered sub-micrometre sized particles (D < 1 ?m) (referred as hyperfine), there are limited studies on particulate composed smaller than the visible infrared wavelengths. We have undertaken an effort determine hyperfine in conjunction with high-porosity, order simulate physical state cometary their related asteroids (P- D-types). In this work, we present a technique developed produce astrophysical relevant materials (silicates, sulphides, macromolecular organics). This is used prepare powders that were measured 0.4–2.6 ?m range. These then included water ice particles, sublimated under vacuum, hyperporous sample material (refers sublimation residue). When grinded below one micrometre, four studied (olivine, smectite, pyroxene amorphous silica), show strong decrease absorption features together blueing spectra. “small grain degeneracy” implies grains should only shallow if any (in case moderately absorbing here). two effects, band depth spectral blueing, magnified when incorporated residue. interpret distinct behaviour between more compact distancing individual size elemental scatterers. work unabundant at S- or V-type asteroids, blue nature B-type may effect rather compositional effect.