The Core Structure of Presolar Graphite Onions

  title={The Core Structure of Presolar Graphite Onions},
  author={Philip Fraundorf and Martin Wackenhut},
  journal={The Astrophysical Journal},
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… Expand

Figures from this paper

Correlated transmission electron microscopy and secondary ion mass spectrometry with submicron spatial resolution (NanoSIMS) investigations of the same presolar graphites spherules from the MurchisonExpand
Laboratory evidence of slow-cooling for carbon droplets in red-giant atmospheres
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 theExpand
Analogs for Unlayered-Graphene Droplet-Formation in Stellar Atmospheres.
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 "Expand
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.Expand
Correlated isotopic and microstructural studies of turbostratic presolar graphites from the Murchison meteorite
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 disorder,Expand
Unconventional Magnetism in All-Carbon Nanofoam
We report production of nanostructured magnetic carbon foam by a high-repetition-rate, high-power laser ablation of glassy carbon in Ar atmosphere. A combination of characterization techniquesExpand
Characterizing Unlayered-Graphene in Homemade Core\Rim Carbon Raindrops
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 aExpand
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 isotopesExpand
The rates of unlayered graphene formation in a supercooled carbon melt at low pressure
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 formedExpand
Diffraction Analysis of Graphene Starsmoke
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 theExpand


Constraints on Stellar Grain Formation from Presolar Graphite in the Murchison Meteorite
We report the results of isotopic, chemical, structural, and crystallographic microanalyses of graphitic spherules (0.3E9 km) extracted from the Murchison meteorite. The spherules have 12C/13C ratiosExpand
The 2175-A feature from irradiated graphitic particles
In diffuse clouds, a subpopulation of the carbon grains is graphitized by UV starlight during cloud lifetimes of roughly 100 Myr. Graphitic dust created in this way will behave like monosize RayleighExpand
▪ Abstract Primitive meteorites contain grains of stardust that originated from stellar outflows and supernova ejecta prior to the formation of the Solar System. The study of these grains in theExpand
Interstellar grains in meteorites: I. Isolation of SiC, graphite and diamond; size distributions of SiC and graphite
A procedure has been developed for isolating three types of interstellar grains from primitive meteorites, in >90% purity and yields of generally ≥70%, and is here applied to the Murchison C2MExpand
Formation of dust particles in cool stellar outflows
The formation of grains in circumstellar outflows is reviewed. Special emphasis is laid on the distinction between the condensation of seed particles and the further growth of these particles servingExpand
Structure of Fullerenes
This chapter illustrates the internal structure of the molecules. Many independent experiments show that the crystalline materials formed from fullerenes are molecular solids. Therefore the structureExpand
The formation of quasi-icosahedral spiral shell carbon particles
A simple, new, carbon nucleation scheme has been developed which results in quasi-single crystal particles of concentric, spiral-shell internal structure and overall quasi-icosahedral shape.Expand
Conditions in stellar outflows inferred from laboratory studies of presolar grains
Presolar grains from meteorites provide direct information on the characteristics of stellar condensates. We review the state of knowledge regarding the origins and properties of presolar grains thatExpand
Presolar material in meteorites: an overview
Primitive meteorites contain grains that originated in stellar outflows and supernova ejecta prior to the formation of the solar system. The study of these presolar grains, whose stellar origin isExpand
Trace‐element concentrations in single circumstellar silicon carbide grains from the Murchison meteorite
— Concentrations of the trace elements Mg, Al, Ca, Ti, V, Fe, Sr, Y, Zr, Ba and Ce were determined by ion microprobe mass spectrometry in 60 individual silicon carbide (SiC) grains (in addition, NbExpand