SODIUM-OXYGEN ANTICORRELATION AND NEUTRON-CAPTURE ELEMENTS IN OMEGA CENTAURI STELLAR POPULATIONS

Journal Article · Sun Apr 10 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/731/1/64· OSTI ID:21574734

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

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1. Max-Planck-Institut fuer Astrophysik, Postfach 1317, D-85741 Garching b. Muenchen (Germany)
2. Department of Astronomy, University of Padova, Vicolo dell'osservatorio 3, 35122 Padova (Italy)
3. Departamento de AstronomIa, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)
4. INAF-Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova (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 Teramo, Via M. Maggini, 64100 Teramo (Italy)
8. Departamento de AstronomIa y Astrofisica, P. Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

Omega Centauri is no longer the only globular cluster known to contain multiple stellar populations, yet it remains the most puzzling. Due to the extreme way in which the multiple stellar population phenomenon manifests in this cluster, it has been suggested that it may be the remnant of a larger stellar system. In this work, we present a spectroscopic investigation of the stellar populations hosted in the globular cluster {omega} Centauri to shed light on its still puzzling chemical enrichment history. With this aim, we used FLAMES+GIRAFFE-VLT to observe 300 stars distributed along the multimodal red giant branch of this cluster, sampling with good statistics the stellar populations of different metallicities. We determined chemical abundances for Fe, Na, O, and n-capture elements Ba and La. We confirm that {omega} Centauri exhibits large star-to-star variations in iron with [Fe/H] ranging from {approx}-2.0 to {approx}-0.7 dex. Barium and lanthanum abundances of metal-poor stars are correlated with iron, up to [Fe/H] {approx}-1.5, while they are almost constant (or at least have only a moderate increase) in the more metal-rich populations. There is an extended Na-O anticorrelation for stars with [Fe/H] {approx}<-1.3 while more metal-rich stars are almost all Na-rich. Sodium was found to mildly increase with iron over the entire metallicity range.

• OSTI ID: 21574734
• Journal Information: Astrophysical Journal, Vol. 731, Issue 1; Other Information: DOI: 10.1088/0004-637X/731/1/64; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BARIUM
ELEMENT ABUNDANCE
IRON
LANTHANUM
NEUTRON REACTIONS
OXYGEN
SODIUM
STAR CLUSTERS
STARS
ABUNDANCE
ALKALI METALS
ALKALINE EARTH METALS
BARYON REACTIONS
ELEMENTS
HADRON REACTIONS
METALS
NONMETALS
NUCLEAR REACTIONS
NUCLEON REACTIONS
RARE EARTHS
TRANSITION ELEMENTS