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Globular Clusters (GCs) are natural laboratories where stellar and chemical evolution can be studied in detail. In addition, their chemical patterns and kinematics can tell us wich Galactic structure (Disk, Bulge, Halo or extragalactic) the…

Solar and Stellar Astrophysics · Physics 2018-01-10 A. Mura-Guzmán , S. Villanova , C. Muñoz , B. Tang

With the aim to constrain multiple populations in the metal-poor globular cluster NGC6397, we analyse and discuss the chemical compositions of a large number of elements in 21 red giant branch stars. High-resolution spectra were obtained…

Solar and Stellar Astrophysics · Physics 2015-05-20 K. Lind , C. Charbonnel , T. Decressin , F. Primas , F. Grundahl , M. Asplund

We present abundances of several light, alpha, Fe-peak, and neutron-capture elements for 66 red giant branch (RGB) stars in the Galactic globular cluster Omega Centauri. Our observations lie in the range 12.0<V<13.5 and focus on the…

Solar and Stellar Astrophysics · Physics 2011-02-11 Christian I. Johnson , Catherine A. Pilachowski , R. Michael Rich , Jon P. Fulbright

We used the multifiber spectrograph FLAMES on the ESO Very Large Telescope UT2 to derive atmospheric parameters, metallicities and abundances of O and Na for 79 red giant stars in the Galactic globular cluster NGC 6218 (M 12). We analyzed…

We present the chemical compositions for eight bright giants in the globular cluster NGC 1851. Our analysis reveals large star-to-star abundance variations and correlations of the light elements O, Na, and Al, a feature found in every well…

Astrophysics · Physics 2009-11-13 David Yong , Frank Grundahl

We investigate the light-element behavior of red giant stars in Northern globular clusters (GCs) observed by the SDSS-III Apache Point Observatory Galactic Evolution Experiment (APOGEE). We derive abundances of nine elements (Fe, C, N, O,…

We present CN and CH indices and CaII triplet metallicities for 34 giant stars and chemical abundances for 33 elements in 14 giants in the globular cluster M2. Assuming the program stars are cluster members, our analysis reveals (i) an…

Among stars in Galactic globular clusters the carbon abundance tends to decrease with increasing luminosity on the upper red giant branch, particularly within the lowest metallicity clusters. While such a phenomena is not predicted by…

Solar and Stellar Astrophysics · Physics 2019-04-08 Jeffrey M. Gerber , Michael M. Briley , Graeme H. Smith

Stellar models for -2.5 <= [Fe/H] <= -0.5 that have been computed for variations in the C:N:O abundance ratio (for two different values of [CNO/Fe]) are compared with HST Wide Field Camera 3 (WFC3) observations of the globular clusters…

Solar and Stellar Astrophysics · Physics 2021-12-15 Don A. VandenBerg , Luca Casagrande , Bengt Edvardsson

Abundances of C, N, and O are determined in four bright red giants that span the known abundance range for light (Na and Al) and s-process (Zr and La) elements in the globular cluster NGC 1851. The abundance sum C+N+O exhibits a range of…

Solar and Stellar Astrophysics · Physics 2009-11-13 David Yong , Frank Grundahl , Francesca D'Antona , Amanda I. Karakas , John C. Lattanzio , John E. Norris

Recent theoretical yields and chemical evolution models demonstrate that intermediate-mass AGB stars cannot reproduce the observed abundance distributions of O, Na, Mg, and Al. As a further observational test of this finding, we present…

We study the distribution of aluminum abundances among red giants in the peculiar globular cluster NGC 1851. Aluminum abundances were derived from the strong doublet Al I 8772-8773 A measured on intermediate resolution FLAMES spectra of 50…

Astrophysics of Galaxies · Physics 2015-06-05 Eugenio Carretta , Valentina D'Orazi , Raffaele G. Gratton , Sara Lucatello

We present a high resolution spectroscopic analysis of 62 red giants in the Milky Way globular cluster NGC5286. We have determined abundances of representative light proton-capture, alpha, Fe-peak and neutron-capture element groups, and…

Detailed chemical abundances of two stars in the intermediate-age Large Magellanic Cloud (LMC) globular cluster NGC~1718 are presented, based on high resolution spectroscopic observations with the MIKE spectrograph. The detailed abundances…

Astrophysics of Galaxies · Physics 2017-02-12 Charli Sakari , Andrew McWilliam , George Wallerstein

We present abundances of globular clusters in the Milky Way and Fornax from integrated light spectra. Our goal is to evaluate the consistency of the integrated light analysis relative to standard abundance analysis for individual stars in…

Astrophysics of Galaxies · Physics 2017-01-11 J. E. Colucci , R. A. Bernstein , A. McWilliam

We present a detailed chemical abundance study of evolved stars in 10 open clusters based on Hydra multi-object echelle spectra obtained with the WIYN 3.5m telescope. From an analysis of both equivalent widths and spectrum synthesis,…

Astrophysics of Galaxies · Physics 2015-05-28 H. R. Jacobson , C. A. Pilachowski , E. D. Friel

Abundance variations in moderately metal-rich globular clusters can give clues about the formation and chemical enrichment of globular clusters. CN, CH, Na, Mg and Al indices in spectra of 89 stars of the template metal-rich globular…

Astrophysics · Physics 2009-11-13 A. Alves-Brito , R. P. Schiavon , B. Castilho , B. Barbuy

High resolution (R > 40 000) and high S/N spectra have been acquired with UVES on the VLT-Kueyen (Paranal Observatory, ESO Chile) for several main sequence turnoff stars (V ~ 17 mag) and subgiants at the base of the Red Giant Branch (V ~ 16…

Astrophysics · Physics 2007-05-23 G. James , P. Francois , P. Bonifacio , E. Carretta , R. G. Gratton , F. Spite

Our understanding of multiple populations in globular clusters (GCs) largely comes from photometry and spectroscopy: appropriate photometric diagrams can disentangle first and second populations (1P and 2P)-1P having chemical signatures…

Context: The study of chemical abundance patterns in globular clusters is of key importance to constrain the different candidates for intra-cluster pollution of light elements. Aims: We aim at deriving accurate abundances for a large range…

Solar and Stellar Astrophysics · Physics 2014-12-10 A. O. Thygesen , L. Sbordone , S. Andrievsky , S. Korotin , D. Yong , S. Zaggia , H. -G. Ludwig , R. Collet , M. Asplund , F. D'Antona , J. Meléndez , A. D'Ercole