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Related papers: Empirical estimates of the Na-O anti-correlation i…

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We analyzed the high-resolution spectra of a large sample of AGB and RGB stars in the Galactic globular clusters (GCs) NGC 104, NGC 6121, and NGC 6809 obtained with FLAMES/GIRAFFE at ESO/VLT, and determined their Na abundances. This is the…

Solar and Stellar Astrophysics · Physics 2017-12-01 Y. Wang , F. Primas , C. Charbonnel , M. Van der Swaelmen , G. Bono , W. Chantereau , G. Zhao

Ancient ($>$10 Gyr) globular clusters (GCs) show chemical abundance variations in the form of patterns among certain elements, e.g. N correlates with Na and anti-correlates with O. Recently, N abundance spreads have also been observed in…

Information on globular clusters (GC) formation mechanisms can be gathered by studying the chemical signature of the multiple populations that compose these stellar systems. In particular, we are investigating the anticorrelations among O,…

Solar and Stellar Astrophysics · Physics 2015-11-04 A. Bragaglia , E. Carretta , A. Sollima , P. Donati , V. D'Orazi , R. G. Gratton , S. Lucatello , C. Sneden

We modify our combined ("deep mixing" plus "primordial") scenario explaining the star-to-star abundance variations in globular cluster red giants in such a way that it confirms with new experimental data: (i) the new and better constrained…

Astrophysics · Physics 2009-11-06 Pavel A. Denissenkov , Achim Weiss

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 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

In the past decade, the notion that globular clusters (GCs) are composed of coeval stars with homogeneous initial chemical compositions has been challenged by growing evidence that they host an intricate stellar population mix, likely…

We searched for trails to understand the different Na abundances measured in first and second generation stars of ancient Milky Way globular clusters. For that purpose, we gathered from the recent literature the aforementioned Na…

Astrophysics of Galaxies · Physics 2020-11-11 Andrés E. Piatti

Open clusters are historically regarded as single-aged stellar populations representative of star formation within the Galactic disk. Recent literature has questioned this view, based on discrepant Na abundances relative to the field, and…

Solar and Stellar Astrophysics · Physics 2015-06-23 B. T. MacLean , G. M. De Silva , J. Lattanzio

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 study the abundances of Na, Mg, and K in the atmospheres of 32 RGB stars in the Galactic globular cluster (GGC) 47 Tuc, with the goal to investigate the possible existence of Na-K and Mg-K correlations/anti-correlations, similar to those…

Solar and Stellar Astrophysics · Physics 2017-08-02 A. Černiauskas , A. Kučinskas , J. Klevas , D. Prakapavičius , S. Korotin , P. Bonifacio , H. -G. Ludwig , E. Caffau , M. Steffen

We present a new method to estimate the fraction of stars with chemical composition of first and second(s) generation(s) currently hosted in Galactic globular clusters (GCs). We compare cluster and field stars of similar metallicity in the…

Astrophysics of Galaxies · Physics 2015-06-16 Eugenio Carretta

The HST UV Survey of Globular Clusters (GCs) has investigated GCs and their stellar populations. In previous papers of this series we have introduced a pseudo two-color diagram, "chromosome map" (ChM), that maximises the separation between…

Solar and Stellar Astrophysics · Physics 2019-05-29 A. F. Marino , A. P. Milone , A. Renzini , F. D'Antona , J. Anderson , L. R. Bedin , A. Bellini , G. Cordoni , E. P. Lagioia , G. Piotto , M. Tailo

We use high-precision photometry of red-giant-branch (RGB) stars in 57 Galactic globular clusters (GCs), mostly from the `Hubble Space Telescope (HST) UV Legacy Survey of Galactic globular clusters', to identify and characterize their…

As sites of some of the most efficient star formation in the Universe, globular clusters (GCs) have long been hypothesized to be the building blocks of young galaxies. Within the Milky Way, our best tracers of the contribution of GCs to the…

In the last years, photometric and spectroscopic evidence has demonstrated that many, maybe all the Globular Clusters (GC) host multiple stellar populations. High-resolution spectroscopy has established that, while most GCs are…

Solar and Stellar Astrophysics · Physics 2011-07-13 A. P. Milone , G. Piotto , R. L. Bedin , A. F. Marino , Y. Momany , S. Villanova

We discuss the self-enrichment scenario by AGB stars for the formation of multiple populations in globular clusters (GCs) by analyzing data set of giant stars observed in 9 Galactic GCs, covering a wide range of metallicities and for which…

Intracluster stellar populations are a natural result of tidal interactions in galaxy clusters. Measuring these populations is difficult, but important for understanding the assembly of the most massive galaxies. The Coma cluster is one of…

Context. Galactic Centre (GC) OH/IR stars can be, based on the expansion velocities of their circumstellar shells, divided into two groups which are kinematically different and therefore are believed to have evolved from different stellar…

Astrophysics · Physics 2009-11-11 E. Vanhollebeke , J. A. D. L. Blommaert , M. Schultheis , B. Aringer , A. Lancon
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