Natural Solid Bitumens as Possible Analogs for Cometary and Asteroid Organics:: 1. Reflectance Spectroscopy of Pure Bitumens

摘要: Abstract Natural solid oil bitumens (asphaltites, kerites, anthraxolites) appear to be useful spectral analogs for cometary and asteroid refractory organics. They show color similarities the surfaces of dark asteroids nuclei, as well compositional structural resemblances organic components carbonaceous chondrites. These solids are composed a variety compounds, most which aromatic aliphatic hydrocarbons. Spectral reflectance measurements in range 0.5–16 μm have been performed on suite bitumen powders. The samples were also characterized by chemical analyses, state13C-NMR, X-ray diffractometry. observed variations between correlate with their composition structure. In near-infrared region parameters found, make it possible derive carbon aromaticities (fa) important elemental ratios (C/(C + H N S O) or H/C). Moreover, these can used estimate some characteristics component (an average interlayer spacingd002and vertical crystallite sizeLc). use same may help reveal presence mineral admixtures when content an organic-rich assemblage is too low any distinct absorption bands minerals.