The Core Structure of Presolar Graphite Onions

@article{Fraundorf2002TheCS,
  title={The Core Structure of Presolar Graphite Onions},
  author={Philip Fraundorf and Martin Wackenhut},
  journal={The Astrophysical Journal Letters},
  year={2002},
  volume={578},
  pages={L153 - L156}
}
Of the "presolar particles" extracted from carbonaceous meteorite dissolution residues, i.e., of those particles that show isotopic evidence of formation in the neighborhood of other stars prior to the origin of our solar system, a subset of the onion-like graphite spheres has an interesting concentric graphene core-graphite rim structure. We show here that single graphene sheet defects in the onion cores (e.g., cyclopentane loops) may be observable edge-on by high-resolution electron… 

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Micron-sized presolar carbon spheres condensed before the origin of our solar system, in the atmosphere of asymptotic giant branch stars from carbon atoms dredged up following nucleosynthesis in the

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The unlayered spherical graphene cores, found in a subset of micron-sized presolar graphite onions extracted from primitive meteorites, show graphene but not graphite inter-sheet spacings, sheet "

Origin and Evolution of Carbonaceous Presolar Grains in Stellar Environments

1507. Lunar and Planetary Institute, Houston (CD- ROM). Croat T. K., Stadermann F. J., and Bernatowicz T. J. (2005b) Presolar graphite from AGB stars: Microstructure and s-process enrichment.

Correlated isotopic and microstructural studies of turbostratic presolar graphites from the Murchison meteorite

Abstract— –We present data from TEM and NanoSIMS investigations of Murchison (CM2) KFC1 presolar graphites. TEM examinations of graphite ultramicrotome sections reveal varying degrees of graphite

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A significant fraction of micron-sized presolar “high-density” graphite onions (e.g. from Murchison KFC1) likely formed in AGB star atmospheres[1], and have concentric graphite shells surrounding a

Fraction Crystalline from Electron Powder Patterns of Unlayered Graphene in Solidified Carbon Rain

Elemental carbon at low (e.g. ambient and lower) pressure sublimates to vapor near 4000K, but liquid carbon is reported after laser ablation [1,2]. Some meteoritic carbon particles, whose isotopes

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Elemental carbon has important structural diversity, ranging from nanotubes to graphite and diamond. Studies of primitive meteorite extracted micron-size core/rim carbon spheres suggest they formed

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Cores of micron-sized graphite spheres from AGB star atmospheres contain our first naturally-occurring samples of solid unlayered-graphene, and may be characteristic of much condensed carbon in the

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