Constraints on the Formation Age of Cometary Material from the NASA Stardust Mission
We measured the {sup 26}Al-{sup 26}Mg isotope systematics of a {approx} 5-micrometer refractory particle, Coki, returned from comet 81P/Wild 2 in order to relate the time scales of formation of cometary inclusions to their meteoritic counterparts. The data show no evidence of radiogenic {sup 26}Mg and define an upper limit to the abundance of {sup 26}Al at the time of particle formation: {sup 26}Al/{sup 27}Al < 1 x 10-5. The absence of {sup 26}Al indicates that Coki formed >1.7 million years after the oldest solids in the solar system, calcium- and aluminum-rich inclusions (CAIs). The data suggest that high-temperature inner solar system material formed, was subsequently transferred to the Kuiper Belt, and was incorporated into comets several million years after CAI formation.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 980892
- Report Number(s):
- LLNL-JRNL-420385; SCEHDK; TRN: US201012%%1339
- Journal Information:
- Science, Vol. 328, Issue 5977; ISSN 0193-4511
- Country of Publication:
- United States
- Language:
- English
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