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Title: Highly concentrated nebular noble gases in porous nanocarbon separates from the Saratov (L4) meteorite

The majority of heavy noble gases (Ar, Kr, and Xe) in primitive meteorites are stored in a poorly understood phase called Q. Although Q is thought to be carbonaceous, the full identity of the phase has remained elusive for almost four decades. In order to better characterize phase Q and, in turn, the early solar nebula, we separated carbon-rich fractions from the Saratov (L4) meteorite. We chose this meteorite because Q is most resistant in thermal alteration among carbonaceous noble gas carriers in meteorites and we hoped that, in this highly metamorphosed meteorite, Q would be present but not diamond: these two phases are very difficult to separate from each other. One of the fractions, AJ, has the highest {sup 132}Xe concentration of 2.1 × 10{sup –6} cm{sup 3} STP g{sup –1}, exceeding any Q-rich fractions that have yet been analyzed. Transmission electron microscopy studies of the fraction AJ and a less Q-rich fraction AI indicate that they both are primarily porous carbon that consists of domains with short-range graphene orders, with variable packing in three dimensions, but no long-range graphitic order. The relative abundance of Xe and C atoms (6:10{sup 9}) in the separates indicates that individual noble gasmore » atoms are associated with only a minor component of the porous carbon, possibly one or more specific arrangements of the nanoparticulate graphene.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. McDonnell Center for the Space Sciences and the Physics Department, Washington University, St. Louis, MO 63130 (United States)
  2. Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan)
  3. Code 6360, Naval Research Laboratory, Washington, DC 20375 (United States)
  4. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)
Publication Date:
OSTI Identifier:
22342032
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 778; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABUNDANCE; ARGON; ATOMS; CONCENTRATION RATIO; DIAMONDS; GRAPHENE; GRAPHITE; KRYPTON; METEORITES; METEOROIDS; NANOSTRUCTURES; POROUS MATERIALS; RARE GASES; SOLAR NEBULA; TRANSMISSION ELECTRON MICROSCOPY; XENON; XENON 132