Zr and Mo isotopic constraints on the origins of unusual types of presolar SiC grains.
Although most presolar silicon carbide grains form in asymptotic giant branch red giant stars (the so-called mainstream grains) or supernovae (the X-grains), there are a number of other minor types of grains whose origin is less clear. The dominant mechanisms of heavy element nucleosynthesis, the s-process and r-process, are thought to occur mainly in AGB stars and supernovae, respectively [1], and the isotopic patterns in heavy elements in presolar grains can be used to constrain their origins. We have previously reported that mainstream SiC grains have strong enrichments in the s-process isotopes of Sr, Zr and Mo [2-5] and that X-grains have an unusual Mo isotopic composition that differs from s- and r-process expectations [6,7]. We report here the first measurements of Zr and Mo isotopes in several grains of other rare types that were found in the same mount as the mainstream and X-grains reported previously.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 768571
- Report Number(s):
- ANL/CHM/CP-101227; TRN: AH200123%%329
- Resource Relation:
- Conference: 31st Lunar and Planetary Science Conference, Houston, TX (US), 03/13/2000--03/17/2000; Other Information: PBD: 1 Mar 2000
- Country of Publication:
- United States
- Language:
- English
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