Nitrogen Isotopic Fractionation in Interstellar Ammonia
- Creators
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Lis, D. C.
- Wootten, A.
- Gerin, M.
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Roueff, E.
Abstract
Using the Green Bank Telescope, we have obtained accurate measurements of the ^(14)N/^(15)N isotopic ratio in ammonia in two nearby cold, dense molecular clouds, Barnard 1 and NGC 1333. The ^(14)N/^(15)N ratio in Barnard 1, 334 ± 50 (3σ), is particularly well constrained and falls in between the local interstellar medium/proto-solar value of ~450 and the terrestrial atmospheric value of 272. The NGC 1333 measurement is consistent with the Barnard 1 result, but has a larger uncertainty. We do not see evidence for the very high ^(15)N enhancements seen in cometary CN. Sensitive observations of a larger, carefully selected sample of prestellar cores with varying temperatures and gas densities can significantly improve our understanding of the nitrogen fractionation in the local interstellar medium and its relation to the isotopic ratios measured in various solar system reservoirs.
Additional Information
© 2010 The American Astronomical Society. Received 2009 November 6; accepted 2009 December 30; published 2010 January 20. We thank T. Minter and the GBT operator, D. Stricklin, for their assistance during the observations and J. Braatz for his advice in setting up the observing scripts. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. D. C. Lis is supported by the National Science Foundation grant AST-0540882 to the Caltech Submillimeter Observatory. M. Gerin and E. Roueff acknowledge support from the CNRS-INSU French National Program PCMI (Physique et Chimie du Milieu Interstellaire).Attached Files
Published - Lis2010p7189Astrophys_J_Lett.pdf
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Additional details
- Eprint ID
- 17613
- Resolver ID
- CaltechAUTHORS:20100301-092329398
- AST-0540882
- NSF
- Centre National de la Recherche Scientifique (CNRS)
- Physique et Chimie du Milieu Interstellaire (PCMI)
- Institut national des sciences de l'Univers (INSU)
- Created
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2010-03-02Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field