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Carbon Isotopes in CometsThis paper is a progress report based on high resolution spectra of selected bright comets with the goal of determining the carbon isotope abundance ratio, 12C/13C. The 12C/13C ratio has been determined for various Solar System objects (in the atmospheres of the giant planets, meteorites, the Earth, and the solar photosphere), where 12C/13C 89/1. In the interstellar medium, optical and radio observations give a range of 12C/12C 43-67/1 depending on the observing techniques used and the specific interstellar cloud observed. For comet P/Halley, Wyckoff et al. (1989 Ap. J., 339, 488) found 12C/13C = 65/1±8. Previous determinations of the 12C/13C ratio in comets by other investigators, involving lower resolution spectra, dealt with the C2 (0,1) Swan system with band heads at 4737 Å for 12C2(0,1) and at 4745 Å for 13C12C(0,1). However, there is an NH2 feature with four lines which coincide with the 13C12C band head, thus making a determination of the 12C/13C ratio very uncertain based on the C2(0,1) band structure.
Document ID
19910011721
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Peter A Wehinger
(Arizona State University Tempe, United States)
Date Acquired
September 6, 2013
Publication Date
June 15, 1990
Publication Information
Publication: Workshop on Observations of Recent Comets (1990)
Publisher: National Aeronautics and Space Administration
Subject Category
Astrophysics
Report/Patent Number
NASA-CR-188960
Meeting Information
Meeting: Workshop on Observations of Recent Comets
Location: Albuquerque, NM
Country: US
Start Date: June 15, 1990
End Date: June 16, 1990
Sponsors: National Aeronautics and Space Administration
Accession Number
91N21034
Funding Number(s)
CONTRACT_GRANT: NAGW-547
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.

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