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Reflectance spectroscopy of insoluble organic matter (IOM) and carbonaceous meteorites
Author(s) -
Kaplan Hannah H.,
Milliken Ralph E.,
Alexander Conel M. O'D.,
Herd Christopher D. K.
Publication year - 2019
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/maps.13264
Subject(s) - meteorite , asteroid , spectral line , context (archaeology) , astrobiology , interplanetary dust cloud , chemistry , chondrite , absorption (acoustics) , reflectivity , parent body , iron meteorite , analytical chemistry (journal) , astrophysics , solar system , geology , physics , astronomy , optics , environmental chemistry , paleontology
Insoluble organic matter (IOM) is the major organic component of chondritic meteorites and may be akin to organic materials from comets and interplanetary dust particles (IDPs). Reflectance spectra of IOM in the range 0.35–25 μm are presented as a tool for interpreting organic chemistry from remote measurements of asteroids, comets, IDPs, and other planetary bodies. Absorptions in the IOM spectra were strongly related to elemental H/C (atom) ratio. The aliphatic 3.4 μm absorption in IOM spectra increased linearly in strength with increasing H/C for H/C > 0.4, but was absent at lower H/C values. When meteorite spectra from the Reflectance Experiment Laboratory (RELAB) spectral catalog ( n = 85) were reanalyzed at 3.4 μm, this detection limit (H/C > 0.4) persisted. Aromatic absorption features seen in IOM spectra were not observed in the meteorite spectra due to overlapping absorptions. However, the 3.4 μm aliphatic absorption strength for the bulk meteorites was correlated with both H/C of the meteorite's IOM and bulk C (wt%). Gaussian modeling of the 3 μm region provided an additional estimate of bulk C for the meteorites, along with bulk H (wt%), which is related to phyllosilicate abundance. These relationships lay the foundation for determining organic and phyllosilicate abundances from reflectance spectra. Both the full IOM spectra and the spectral parameters discussed here will aid in the interpretation of data from asteroid missions (e.g., OSIRIS‐REx, Hayabusa2), and may be able to place unknown spectral samples within the context of the meteorite collection.