THE C+N+O ABUNDANCE OF {omega} CENTAURI GIANT STARS: IMPLICATIONS FOR THE CHEMICAL-ENRICHMENT SCENARIO AND THE RELATIVE AGES OF DIFFERENT STELLAR POPULATIONS

Journal Article · Fri Feb 10 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/746/1/14· OSTI ID:22011852

Marino, A F ^[1]; Milone, A P; Aparicio, A ^[2]; Piotto, G ^[3]; Cassisi, S ^[4]; D'Antona, F ^[5]; Anderson, J ^[6]; Bedin, L R; Renzini, A ^[7]; Villanova, S ^[8]

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1. Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching bei Muenchen (Germany)
2. Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife, Canary Islands (Spain)
3. Dipartimento di Astronomia, Universita di Padova, Vicolo dell'Osservatorio 3, Padova, I-35122 (Italy)
4. INAF-Osservatorio Astronomico di Teramo, Via M. Maggini, 64100 Teramo (Italy)
5. INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio (Italy)
6. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
7. INAF-Osservatorio Astronomico di Padova, Vicolo dellOsservatorio 5, 35122 Padova (Italy)
8. Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)

We present a chemical-composition analysis of 77 red-giant stars in Omega Centauri. We have measured abundances for carbon and nitrogen, and combined our results with abundances of O, Na, La, and Fe that we determined in our previous work. Our aim is to better understand the peculiar chemical-enrichment history of this cluster by studying how the total C+N+O content varies among the different metallicity stellar groups, and among stars at different places along the Na-O anticorrelation. We find that the (anti)correlations among the light elements that would be expected on theoretical grounds for matter that has been nuclearly processed via high-temperature proton captures. The overall [(C+N+O)/Fe] increases by {approx}0.5 dex from [Fe/H] {approx}-2.0 to [Fe/H] {approx}-0.9. Our results provide insight into the chemical-enrichment history of the cluster, and the measured CNO variations provide important corrections for estimating the relative ages of the different stellar populations.

• OSTI ID: 22011852
• Journal Information: Astrophysical Journal, Vol. 746, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
CARBON
CHEMICAL COMPOSITION
NITROGEN
RED GIANT STARS