Na-O Anticorrelation and HB. II. The Na-O anticorrelation in the globular cluster NGC 6752

Abstract

We are studying the Na-O anticorrelation in several globular clusters of different Horizontal Branch (HB) morphology in order to derive a possible relation between (primordial) chemical inhomogeneities and morphological parameters of the cluster population. We used the multifiber spectrograph FLAMES on the ESO Very Large Telescope UT2 and derived atmospheric parameters and elemental abundances of Fe, O and Na for about 150 red giant stars in the Galactic globular cluster NGC 6752. The average metallicity we derive is [Fe/H]=-1.56, in agreement with other results from red giants, but lower than obtained for dwarfs or early subgiants. In NGC 6752 there is not much space for an intrinsic spread in metallicity: on average, the rms scatter in [Fe/H] is 0.037+/-0.003 dex, while the scatter expected on the basis of the major error sources is 0.039+/-0.003 dex. The distribution of stars along the Na-O anticorrelation is different to what was found in the first paper of this series for the globular cluster NGC 2808: in NGC 6752 it is skewed toward more Na-poor stars, and it resembles more the one in M 13. Detailed modeling is required to clarify whether this difference may explain the very different distributions of stars along the HB.

13 pages, 8 figures; tables 2,3,5 available at CDS. Accepted for publication on A&A

References in corpus (2)

• On the self-enrichment scenario of galactic globular clusters: Constraints on the IMF
• The lack of close binaries among hot horizontal branch stars in NGC6752

Cited by in corpus (15)

• Origin of the abundance patterns in Galactic globular clusters: constraints on dynamical and chemical properties of globular clusters
• Light nuclei in galactic globular clusters : constraints on the self-enrichment scenario from nucleosynthesis
• Looking outside the Galaxy: the discovery of chemical anomalies in 3 old Large Magellanic Cloud clusters
• Measuring Consistent Masses for 25 Milky Way Globular Clusters
• Na-O Anticorrelation and HB. VI. The chemical composition of the peculiar bulge globular cluster NGC 6388
• The evolution of two stellar populations in globular clusters I. The dynamical mixing timescale
• Atomic Diffusion and Mixing in Old Stars V: A deeper look into the Globular Cluster NGC 6752
• The Chemical Evolution of Globular Clusters I. Reactive Elements and Non-Metals
• Na-O Anticorrelation and HB. IV. Detection of He-rich and He-poor stellar populations in the globular cluster NGC 6218
• Three discrete groups with homogeneous chemistry along the red giant branch in the globular cluster NGC 2808
• The link between chemical anomalies along the red giant branch and the horizontal branch extension in globular clusters
• Detailed Abundances of 15 Stars in the Metal-Poor Globular Cluster NGC 4833
• On the missing second generation AGB stars in NGC6752
• Evolution of long-lived globular cluster stars I. Grid of stellar models with helium enhancement at [Fe/H] = -1.75
• Dynamical mixing of two stellar populations in globular clusters