Extreme 26Mg and 17O Enrichments in an Orgueil Corundum: Identification of a Presolar Oxide Grain
Abstract
A corundum (Al2O3) grain from the Orgueil meteorite is greatly enriched in O-17 and (Mg-26)*. The measured O-16/O-17 is 1028 +/- 11 compared to solar(O-16/O-17) = 2610. This is the largest O-17 excess so far observed in any meteoritic material. The Mg-26 excess ((Mg-26)*) is most plausibly due to in situ decay of Al-26. The inferred (Al-26/Al-27)0 ratio of 8.9 x 10-4 is approximately 18 times larger than the 5 x 10-5 value commonly observed in refractory inclusions formed in the solar system. The large O-17 excess and high (Mg-26)* Al-27 ratio unambiguously identify this corundum as a presolar oxide grain. Enrichments in O-17 and Al-26 are characteristic of H-burning and point to red giant or asymptotic giant branch (AGB) stars as likely sources.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1994
- DOI:
- Bibcode:
- 1994ApJ...425L..97H
- Keywords:
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- Aluminum Isotopes;
- Aluminum Oxides;
- Magnesium Isotopes;
- Orgueil Meteorite;
- Oxygen Isotopes;
- Solar System Evolution;
- Asymptotic Giant Branch Stars;
- Cosmic Dust;
- Interstellar Extinction;
- Red Giant Stars;
- Stellar Envelopes;
- Astronomy;
- STARS: CIRCUMSTELLAR MATTER;
- ISM: DUST;
- EXTINCTION;
- NUCLEAR REACTIONS;
- NUCLEOSYNTHESIS;
- ABUNDANCES;
- STARS: AGB AND POST-AGB;
- SOLAR SYSTEM: FORMATION