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Title: A TEM, C-XANES and NanoSIMS Investigation of a Fragment from the Stardust Track ADA


No abstract prepared.

; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
Report Number(s):
TRN: US1005845
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Meteoritics and Planetary Science; Journal Volume: 42
Country of Publication:
United States

Citation Formats

Matrajt,G., Wirick, S., Messenger, S., Ito, M., Joswiak, D., and Brownlee, D.. A TEM, C-XANES and NanoSIMS Investigation of a Fragment from the Stardust Track ADA. United States: N. p., 2007. Web.
Matrajt,G., Wirick, S., Messenger, S., Ito, M., Joswiak, D., & Brownlee, D.. A TEM, C-XANES and NanoSIMS Investigation of a Fragment from the Stardust Track ADA. United States.
Matrajt,G., Wirick, S., Messenger, S., Ito, M., Joswiak, D., and Brownlee, D.. Mon . "A TEM, C-XANES and NanoSIMS Investigation of a Fragment from the Stardust Track ADA". United States. doi:.
title = {A TEM, C-XANES and NanoSIMS Investigation of a Fragment from the Stardust Track ADA},
author = {Matrajt,G. and Wirick, S. and Messenger, S. and Ito, M. and Joswiak, D. and Brownlee, D.},
abstractNote = {No abstract prepared.},
doi = {},
journal = {Meteoritics and Planetary Science},
number = ,
volume = 42,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
  • In this work we present the results of a systematic search for cometary organics in 14 Stardust particles (particles from comet 81P/Wild 2, captured by NASA's Stardust mission) by TEM and multidisciplinary studies (XANES and NanoSIMS) of Febo and Ada, two of the organic-bearing particles identified. The combination of the three analytical techniques has established the presence of organic, cometary C in both particles. Using energy-filtered and high-resolution imaging it was shown that the C is amorphous and rare, given that it is found in grains =200 nm in size that are not abundant throughout the particles. The XANES mapsmore » and spectra of the carbonaceous areas identified with the TEM have shown that the carbonaceous material is organic due to the presence of carbonyl (C=O) functional groups and the overlapping of C and N on the same grains. In addition, several different C-XANES spectra were obtained from the same particle, suggesting that there is diversity in the types of carbonaceous phases present in these particles, as well as a heterogeneous distribution of the carbonaceous phases within these particles. The C-XANES spectra obtained are different from C-XANES spectra of carbonaceous chondrites and IDPs. In the particle Febo we found five spots showing a pronounced enrichment in the isotope {sup 15}N ({sigma}{sup 15} ffffrom 420 to 639 {+-} 20 to 70%, 1S) that were clearly associated with the C-rich regions. The carbonaceous material has approximately solar C and D/H isotopic compositions, and the bulk O isotopic composition was found to be S{sup 17} O=-18 {+-} 13% and {sigma}{sup 18} O=-37 {+-}12% (aS).« less
  • We report on isotopic and microstructural investigations of a unique presolar supernova (SN) graphite grain, referred to as G6, isolated from the Orgueil CI chondrite. G6 contains complex heterogeneities in its isotopic composition and in its microstructure. Nano-scale secondary ion mass spectrometer isotope images of ultramicrotome sections reveal heterogeneities in its C, N, and O isotopic compositions, including anomalous shell-like structures. Transmission electron microscope studies reveal a nanocrystalline core surrounded by a turbostratic graphite mantle, the first reported nanocrystalline core from a low-density SN graphite grain. Electron diffraction analysis shows that the nanocrystalline core consists of randomly oriented 2-4 nmmore » graphene particles, similar to those in cores of high-density (HD) presolar graphite grains from asymptotic giant branch stars. G6's core also exhibits evidence for planar stacking of these graphene nano-sheets with a domain size up to 4.5 nm, which was unobserved in the nanocrystalline cores of HD graphite grains. We also report on X-ray absorption near-edge structure measurements of G6. The complex isotopic- and micro-structure of G6 provides evidence for mixing and/or granular transport in SN ejecta.« less
  • Cited by 1
  • We report new O isotopic data on 41 presolar oxide grains, 38 MgAl{sub 2}O{sub 4} (spinel) and 3 Al{sub 2}O{sub 3} from the CM2 meteorite Murray, identified with a recently developed automated measurement system for NanoSIMS. We have also obtained Mg-Al isotopic results on 29 of the same grains (26 spinel and 3 Al{sub 2}O{sub 3}). The majority of the grains have O isotopic compositions typical of most presolar oxides, fall well into the four previously defined groups, and are most likely condensates from either red giant branch or asymptotic giant branch stars. We have also discovered several grains withmore » more unusual O and Mg compositions suggesting formation in extreme astrophysical environments, such as novae and supernovae (SNe). One of these grains has massive enrichments in {sup 17}O, {sup 25}Mg, and {sup 26}Mg, which are isotopic signatures indicative of condensation from nova ejecta. Two grains of SN origin were also discovered: one has a large {sup 18}O/{sup 16}O ratio typical of Group 4 presolar oxides; another grain is substantially enriched in {sup 16}O, and also contains radiogenic {sup 44}Ca from the decay of {sup 44}Ti, a likely condensate from material originating in the O-rich inner zones of a Type II SN. In addition, several Group 2 presolar spinel grains also have large {sup 25}Mg and {sup 26}Mg isotopic anomalies that are difficult to explain by standard nucleosynthesis in low-mass stars. Auger elemental spectral analyses were performed on the grains and qualitatively suggest that presolar spinel may not have higher-than-stoichiometric Al/Mg ratios, in contrast to SIMS results obtained here and reported previously.« less
  • New experimental data on the mean-multiplicity distribution of fragments whose charge number ranges between one and eight and on the distribution of the mean kinetic energy of few-nucleon fragments (A = 1-3) are presented versus the 4-momentum transfer from the target proton to the oxygen nucleus in {sup 16}Op collisions at a momentum of 3.25 GeV/c per nucleon. These data are systematically compared with the predictions of the cascade-fragmentation-evaporation model.