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The C, N, and O abundances of giant stars in ω Centauri

Cohen, J. G. and Bell, R. A. (1986) The C, N, and O abundances of giant stars in ω Centauri. Astrophysical Journal, 305 . pp. 698-713. ISSN 0004-637X. doi:10.1086/164284.

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Indices measuring the strength of CH, C_2, CN, and NH bands and Ca ii and Ca i lines have been determined for 72 stars in ω Cen. These data, and narrow-band photometry of the 2.4 µm CO bands, are calibrated by using theoretical indices derived from synthetic spectra which are computed via a grid of model atmospheres of appropriate parameters. In addition to the four C stars, we find two groups of giants in co Cen. Both groups include stars spanning a wide range of abundances of the heavy elements, Z. The N-enhanced stars have N/Z enhanced by a factor of 5 to 15, while both C/Z and O/Z are depleted by a factor which may be as much as 10. This depletion allows the CH and CO features to be fitted satisfactorily and yields enough nitrogen to fit CN and NH features. The N-normal stars have N/Z and C/Z within factor of 2 of solar. The range of variation of C and N is typical of those seen in other globular clusters

Item Type:Article
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Cohen, J. G.0000-0002-8039-4673
Alternate Title:The C, N, and O abundances of giant stars in Omega Centauri
Additional Information:© American Astronomical Society • Provided by the NASA Astrophysics Data System. Received 1985 August 9; accepted 1985 December 4. J. G. C. is grateful to NSF grant AST 82-12270 for support. The work of R. A. B. on this project was supported by both funds and supercomputer time from NSF grant AST 80-19570 after 9/1/84. The indices were computed using a Cray I-S of Boeing Computing Services, the University of Maryland Computer Science Center’s Univac 1182, and a Ridge 32 C. The assistance of Mr. J. Ohlmacher with the calculations is gratefully acknowledged.
Funding AgencyGrant Number
NSFAST 82-12270
NSFAST 80-19570
Subject Keywords:clusters: globular — stars: abundances — stars: evolution — stars: late-type
Record Number:CaltechAUTHORS:20190531-091633440
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95997
Deposited By: George Porter
Deposited On:03 Jun 2019 22:20
Last Modified:16 Nov 2021 17:17

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