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

200 papers

We present the LTE abundance analysis of high resolution spectra for red giant stars in the peculiar bulge globular cluster NGC 6388. Spectra of seven members were taken using the UVES spectrograph at the ESO VLT2 and the multiobject FLAMES…

Homogeneous abundances of light elements, alpha and Fe-group elements from high-resolution FLAMES spectra are presented for 76 red giant stars in M54, a massive globular cluster (GC) lying in the nucleus of the Sagittarius dwarf galaxy. We…

Astrophysics of Galaxies · Physics 2015-05-19 E. Carretta , A. Bragaglia , R. G. Gratton , S. Lucatello , M. Bellazzini , G. Catanzaro , F. Leone , Y. Momany , G. Piotto , V. D'Orazi

Self-enrichment processes occurring in the early stages of a globular cluster lifetime are generally invoked to explain the observed CNONaMgAl abundance anticorrelations within individual Galactic globulars.We have tested, with fully…

Astrophysics · Physics 2009-11-11 Maurizio Salaris , Achim Weiss , Jason W. Ferguson , David J. Fusilier

We present the abundance analysis of stars from the tip of the red giant branch (RGB) to below the RGB-bump in the globular cluster NGC 2808, based on high resolution echelle spectra. We derived abundances of Al, alpha-process elements (Si…

Astrophysics · Physics 2009-11-11 Eugenio Carretta

There is vast evidence from observations of multiple stellar populations (MPs) in globular clusters (GCs). To explore the issue theoretically, this work considers two subsolar metallicities, two ages, and two initial abundance patterns: a…

A self-consistent model of the chemical evolution of the globular cluster NGC 6752 is presented to test a popular theory that observed abundance anomalies are due to ``internal pollution'' from intermediate mass asymptotic giant branch…

Astrophysics · Physics 2009-11-10 Y. Fenner , S. Campbell , A. I. Karakas , J. C. Lattanzio , B. K. Gibson

We present CN and CH band measurements for 137 RGB and AGB stars in the Galactic globular cluster M10. Our measurements come from low resolution spectroscopy taken with the Hydra spectrograph on the WIYN-3.5m telescope. We use these…

Solar and Stellar Astrophysics · Physics 2018-06-12 Jeffrey M. Gerber , Eileen D. Friel , Enrico Vesperini

We studied the Na-O anti-correlation from moderately high resolution spectra for 35 stars on the blue HB (BHB), one RR Lyrae, and 55 stars are on the red HB (RHB) of NGC1851. We also derived abundances for He and N in BHB stars, and Ba and…

Solar and Stellar Astrophysics · Physics 2015-06-03 R. G. Gratton , S. Lucatello , E. Carretta , A. Bragaglia , V. D'Orazi , Y. Al Momany , A. Sollima , M. Salaris , S. Cassisi

We describe the detailed chemical abundance analysis of a high-resolution (R~35,000), integrated-light (IL), spectrum of the core of the Galactic globular cluster 47 Tuc, obtained using the du Pont echelle at Las Campanas. We develop an…

Astrophysics · Physics 2009-11-13 Andrew McWilliam , Rebecca A. Bernstein

Recent JWST observations have revealed a growing population of galaxies at $z>4$ with elevated nitrogen-to-oxygen ratios. These "N/O-enhanced" galaxies (NOEGs) exhibit near- to super-solar N/O at sub-solar O/H, clearly deviating from the…

We used FLAMES+GIRAFFE (Medusa mode) at the VLT to obtain moderately high resolution spectra for 30 red horizontal branch (RHB) stars, 4 RR Lyrae variables, and 17 blue horizontal branch (BHB) stars in the low-concentration, moderately…

Solar and Stellar Astrophysics · Physics 2014-12-24 R. G. Gratton , S. Lucatello , A. Sollima , E. Carretta , A. Bragaglia , Y. Momany , V. D'Orazi , M. Salaris , S. Cassisi , P. B. Stetson

Galactic globular clusters (GC) are known to have multiple stellar populations and be characterised by similar chemical features, e.g. O-Na anti-correlation. While second-population stars, identified by their Na overabundance, have been…

Solar and Stellar Astrophysics · Physics 2016-07-27 Y. Wang , F. Primas , C. Charbonnel , M. Van der Swaelmen , G. Bono , W. Chantereau , G. Zhao

The chemical composition of multiple populations in the massive globular cluster (GC) NGC~2808 is addressed with the homogeneous abundance re-analysis of 140 red giant branch (RGB) stars. UVES spectra for 31 stars and GIRAFFE spectra for…

Solar and Stellar Astrophysics · Physics 2015-09-23 Eugenio Carretta

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

Context. Galactic Globular Clusters (GCs) are essential tools to understand the earliest epoch of the Milky Way, since they are among the oldest objects in the Universe and can be used to trace its formation and evolution. Current studies…

Solar and Stellar Astrophysics · Physics 2017-09-06 C. Muñoz , S. Villanova , D. Geisler , I. Saviane , B. Dias , R. E. Cohen , F. Mauro

The majority of Galactic globular clusters (GCs) contain multiple stellar populations displaying specific chemical abundance variations. In particular, GCs generally contain a `primordial' population with abundances similar to field stars,…

Astrophysics of Galaxies · Physics 2023-02-01 E. Leitinger , H. Baumgardt , I. Cabrera-Ziri , M. Hilker , E. Pancino

Recent work has shown that most globular clusters have at least two chemically distinct components, as well as cluster-to-cluster differences in the mean [O/Fe], [Mg/Fe], and [Si/Fe] ratios at similar [Fe/H] values. In order to investigate…

Solar and Stellar Astrophysics · Physics 2015-06-05 Don A. VandenBerg , Peter A. Bergbusch , Aaron Dotter , Jason W. Ferguson , Georges Michaud , Jacques Richer , Charles Proffitt

Our work focuses on the understanding of the origin of CNO-anomalies, which have been detected in several Galactic globular clusters (GCs). This study is based on a homogeneous data set of hundreds of medium resolution spectra of stars in…

Astrophysics · Physics 2009-11-13 Andrea Kayser , Michael Hilker , Eva K. Grebel , Philip G. Willemsen

We test the performance of our analysis technique for integrated-light spectra by applying it to seven well-studied Galactic GCs that span a wide range of metallicities. Integrated-light spectra were obtained by scanning the slit of the…

Solar and Stellar Astrophysics · Physics 2017-05-10 S. S. Larsen , J. P. Brodie , J. Strader

The abundance of fluorine in a few Galactic globular clusters is known to strongly vary from star-to-star. These unexpected chemical properties are an additional confirmation of the chemical inhomogeneities already found in several GC, and…

Solar and Stellar Astrophysics · Physics 2015-06-16 P. de Laverny , A. Recio-Blanco