Extreme deuterium enrichment of organic radicals in the Orgueil meteorite: Revisiting the interstellar interpretation?

摘要: Abstract The insoluble organic matter of the carbonaceous meteorites contains radicals having a polyaromatic structure and heterogeneous distribution. By using Hyperfine Sublevel Correlation spectroscopy (HYSCORE) in pulsed Electron Paramagnetic Resonance (pulsed-EPR), whereby nuclear frequencies magnetic nuclei their hyperfine interaction with electron spin are detected high resolution, shown to be considerably enriched deuterium Orgueil meteorite, D/H ratio 1.5 ± 0.5 × 10−2. These hold 3.6 ± 1.2 × 10−3 H relative total H. Analysis hydrogen interactions indicates that atoms localized benzylic position, on aliphatic carbons bonded aromatic radical moieties. This type C–H bond exhibits one smallest energy, reinforcing recent finding lower energy higher deuterium-enrichment (Remusat L., Palhol F., Robert Derenne S. France-Lanord C. (2006) Enrichment from primitive meteorites: solar system origin? Earth Planet. Sci. Lett. 243, 15–25). Such behavior is difficult reconcile usual interpretation according which ratios represent survivals interstellar grains. More likely, process took place after formation grains whose initial isotopic compositions was close protosolar ratio. were possibly loaded at surface disk where they exposed intense UV irradiation, triggering an exchange deuterium-rich highly reactive ions.