Interstellar exposure ages of large presolar sic grains from the murchison meteorite

Frank Gyngard, Sachiko Amari, Ernst Zinner, U. Ott

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

We report the Li isotopic compositions of nine large, greater than 5 m, presolar SiC grains from the Murchison(CM) meteorite. Most of the SiC grains analyzed are isotopically similar in C and Si and morphologicallydistinct from other presolar SiC grains. Their 7Li/6Li ratios range from ̃9.3 to the solar value (̃12). The6Li enrichments observed in the grains can only arise from galactic cosmic ray spallation off C atoms during travelthrough the interstellar medium (ISM) and before incorporation into the meteorite parent body. Using appropriateproduction rates, we calculate recoil-loss-corrected individual exposure ages of eight grains with 6Li excessesthat range from 40 Myr to about 1 Gyr. The long exposure ages (>500 Myr) are consistent with calculationsof grain survival lifetimes in the ISM, while the shorter ages (

Original languageEnglish
Pages (from-to)359-366
Number of pages8
JournalAstrophysical Journal
Volume700
Issue number2
DOIs
Publication statusPublished - 2009

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Murchison meteorite
parent body
meteorite
cosmic ray
isotopic composition
meteorite parent bodies
spallation
exposure
life (durability)

Keywords

  • Circumstellar matter
  • Cosmic rays
  • ISM: kinematics and dynamics
  • Shock waves
  • Stars: winds, outflows

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Interstellar exposure ages of large presolar sic grains from the murchison meteorite. / Gyngard, Frank; Amari, Sachiko; Zinner, Ernst; Ott, U.

In: Astrophysical Journal, Vol. 700, No. 2, 2009, p. 359-366.

Research output: Contribution to journalArticle

Gyngard, Frank ; Amari, Sachiko ; Zinner, Ernst ; Ott, U. / Interstellar exposure ages of large presolar sic grains from the murchison meteorite. In: Astrophysical Journal. 2009 ; Vol. 700, No. 2. pp. 359-366.
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