Chemical composition of stellar populations in ω Centauri

Marino, A. F.; Piotto, G.; Gratton, R.; Milone, A. P.; Zoccali, M.; Bedin, L. R.; Villanova, S.; Bellini, A.
Bibliographical reference

Light Elements in the Universe, Proceedings of the International Astronomical Union, IAU Symposium, Volume 268, p. 183-184

Advertised on:
4
2010
Number of authors
8
IAC number of authors
0
Citations
13
Refereed citations
11
Description
We derive abundances of Fe, Na, O, α and s-elements from GIRAFFE@VLT spectra for more than 200 red giant stars in the Milky Way satellite ω Centauri. Our preliminary results are that: (i) we confirm that ω Centauri exhibits large star-to-star metallicity variation (~1.4 dex); (ii) the metallicity distribution reveals the presence of at least five stellar populations with different [Fe/H]; (iii) a distinct Na-O anticorrelation is clearly observed for the metal-poor and metal-intermediate stellar populations while apparently the anticorrelation disappears for the most metal rich populations. Interestingly the Na level grows with iron.