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Na-O anticorrelation and HB. VII. The chemical composition of first and second-generation stars in 1
We present abundances of Fe, Na, and O for 1409 red giant stars in 15 galactic globular clusters (GCs), derived from the homogeneous analysis of high-resolution FLAMES/GIRAFFE spectra. Combining the
The horizontal branch (HB) morphology of globular clusters (GCs) is most strongly influenced by metallicity. The second parameter phenomenon, first described in the 1960s, acknowledges that
Metallicities on the double main sequence of ω centauri imply large helium enhancement
Having shown in a recent paper that the main sequence of ? Centauri is split into two distinct branches, we now present spectroscopic results showing that the bluer sequence is less metal-poor. We
A triple main sequence in the globular cluster NGC 2808
Accurate photometry with HST's ACS shows that the main sequence (MS) of the globular cluster NGC 2808 splits into three separate branches. The three MS branches may be associated with the
The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters without Previous Hubble Space Telescope Photometry
We present the first results of a large Advanced Camera for Surveys (ACS) survey of Galactic globular clusters. This Hubble Space Telescope (HST) Treasury project is designed to obtain photometry
The ACS survey of Galactic globular clusters. XII. Photometric binaries along the main sequence
Context. The fraction of binary stars is an important ingredient to interpret globular cluster dynamical evolution and their stellar population. Aims. We investigate the properties of main-sequence
Detailed abundances of a large sample of giant stars in M 54 and in the Sagittarius nucleus
Homogeneous abundances of light elements, α-elements, and Fe-group elements from high-resolution FLAMES spectra are presented for 76 red giant stars in NGC 6715 (M 54), a massive globular cluster
HST color-magnitude diagrams of 74 galactic globular clusters in the HST F439W and F555W bands ⋆
We present the complete photometric database and the color-magnitude diagrams for 74 Galactic globular clusters observed with the HST/WFPC2 camera in the F439W and F555W bands. A detailed discussion
NGC 6791: An Exotic Open Cluster or the Nucleus of a Tidally Disrupted Galaxy?
We report on high-resolution echelle spectroscopy of 20 giant stars in the Galactic old open cluster NGC 6791, obtained with Hydra at the WIYN telescope. High-precision radial velocity allows us to