Presolar graphite from the murchison meteorite: Imprint of nucleosynthesis and grain formation

  • Sachiko Amari
  • , Roberto Gallino
  • , Marco Limongi
  • , Alessandro Chieffi

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

6 Scopus citations

Abstract

Presolar graphite is the carrier of Ne-E(L) and most 22Ne in Ne-E(L) had long been attributed to radiogenic decay of 22Na from novae. Of presolar graphite grains with a range of density (1.6-2.2g/cm 3), low-density graphite grains extracted from the Murchison meteorite are characterized by 18O excesses and Si isotopic anomalies and are believed to have formed in supenova ejecta. From noble gas analyses of low-density graphite grains, we conclude that 22Ne in the grains is from the in situ decay of 22Na (T1/2=2.6a) produced in the C-burning zone in presupernova stars. The grains also contain Kr that was produced by neutron capture, either in the He-burning zone or the C-burning zone during hydrostatic burning. The 22Ne of a 22Na origin indicates that the grains formed shortly after the explosion. The presence of 22Ne of a 22Na origin and Kr, and the absence of 22Ne of a non-radiogenic origin might give us a further clue for graphite formation in supernova ejecta.

Original languageEnglish
Title of host publicationORIGIN OF MATTER AND EVOLUTION OF GALAXIES
Subtitle of host publicationInternational Symposium on Origin of Matter and Evolution of Galaxies 2005: New Horizon of Nuclear Astrophysics and Cosmology
Pages311-318
Number of pages8
DOIs
StatePublished - 2006
EventORIGIN OF MATTER AND EVOLUTION OF GALAXIES: International Symposium on Origin of Matter and Evolution of Galaxies 2005: New Horizon of Nuclear Astrophysics and Cosmology - Tokyo, Japan
Duration: Nov 8 2005Nov 11 2005

Publication series

NameAIP Conference Proceedings
Volume847
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

ConferenceORIGIN OF MATTER AND EVOLUTION OF GALAXIES: International Symposium on Origin of Matter and Evolution of Galaxies 2005: New Horizon of Nuclear Astrophysics and Cosmology
Country/TerritoryJapan
CityTokyo
Period11/8/0511/11/05

Keywords

  • Dust
  • Meteorite
  • Ne-E(L)
  • Nucleosynthesis
  • Slow neutron capture process
  • Supernovae

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