PROTO-PLANETARY DISK CHEMISTRY RECORDED BY D-RICH ORGANIC RADICALS IN CARBONACEOUS CHONDRITES
- Laboratoire de Mineralogie et Cosmochimie du Museum, UMR7202, Museum National d'Histoire Naturelle, 57 rue Cuvier, Case 52, 75005 Paris (France)
- Laboratoire de Chimie de la Matiere Condensee de Paris, UMR CNRS 7574, ENSCP, 11 rue Pierre et Marie Curie, 75005 Paris (France)
- Laboratoire de Geochimie organique et minerale de l'environnement, UMR CNRS 7618, BioEMCo, UPMC, 4 place Jussieu, 75252 Paris Cedex 05 (France)
Insoluble organic matter (IOM) in primitive carbonaceous meteorites has preserved its chemical composition and isotopic heterogeneity since the solar system formed {approx}4.567 billion years ago. We have identified the carrier moieties of isotopically anomalous hydrogen in IOM isolated from the Orgueil carbonaceous chondrite. Data from high spatial resolution, quantitative isotopic NanoSIMS mapping of Orgueil IOM combined with data from electron paramagnetic resonance spectroscopy reveals that organic radicals hold all the deuterium excess (relative to the bulk IOM) in distinct, micrometer-sized, D-rich hotspots. Taken together with previous work, the results indicate that an isotopic exchange reaction took place between pre-existing organic compounds characterized by low D/H ratios and D-rich gaseous molecules, such as H{sub 2}D{sup +} or HD{sub 2} {sup +}. This exchange reaction most likely took place in the diffuse outer regions of the proto-planetary disk around the young Sun, offering a model that reconciles meteoritic and cometary isotopic compositions of organic molecules.
- OSTI ID:
- 21307692
- Journal Information:
- Astrophysical Journal, Vol. 698, Issue 2; Other Information: DOI: 10.1088/0004-637X/698/2/2087; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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