Tuesday, January 15, 2013

1301.2994 (A. O. Thygesen et al.)

Fundamental parameters of red giants in 47 Tucanae    [PDF]

A. O. Thygesen, L. Sbordone
In these proceedings we present initial results of a spectroscopic analysis of a small sample of evolved K-giants in the globular cluster 47 Tucanae. We derive the effective temperature, surface gravity and microturbulence of all targets using standard methods. Further we derive LTE abundances of [Fe/H] and [O/Fe] as well as the abundance of sodium, using NLTE corrections. We find a mean metallicity for the cluster of [Fe/H]$=-0.75\pm0.10$, in excellent agreement with several other studies. Also, we confirm the sodium-oxygen anticorrelation previously reported by a number of other authors. Finally, we see indications of the sodium enriched stars also being enriched in heavy magnesium isotopes.
View original: http://arxiv.org/abs/1301.2994

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