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

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We obtained high-resolution spectra for 94 candidate stars belonging to the HB of M22 with FLAMES. The HB stars we observed span a restricted temperature range (7,800<Teff<11,000 K), where about 60% of the HB stars of M22 are. Within our…

Solar and Stellar Astrophysics · Physics 2014-03-05 R. G. Gratton , S. Lucatello , A. Sollima , E. Carretta , A. Bragaglia , Y. Momany , V. D'Orazi , S. Cassisi , M. Salaris

We have carried out a detailed abundance analysis for 21 elements in a sample of 25 stars with a wide range in luminosity from luminous giants to stars near the main sequence turnoff in the globular cluster M13 and in a sample of 13 stars…

Astrophysics · Physics 2009-10-12 Judith G. Cohen , Jorge Melendez

The origin of the star-to-star abundance variations found for the light elements in Galactic globular clusters (GGCs) is not well understood, which is a significant problem for stellar astrophysics. While the light element abundance…

Solar and Stellar Astrophysics · Physics 2019-01-23 C. Salgado , G. S. Da Costa , J. E. Norris , D. Yong

We present the results of determination of the age, helium mass fraction (Y) in terms of the used stellar evolutionary models, metallicity ([Fe/H]), and abundances of the elements C, O, Na, Mg, Ca, Ti, Cr and Mn for 26 globular clusters of…

Astrophysics of Galaxies · Physics 2020-09-07 M. E. Sharina , V. V. Shimansky , N. N. Shimanskaya

Almost all globular clusters investigated exhibit a spread in their light element abundances, the most studied being a Na:O anticorrelation. In contrast, open clusters show a homogeneous composition and are still regarded as Simple Stellar…

Astrophysics of Galaxies · Physics 2015-06-05 D. Geisler , S. Villanova , G. Carraro , C. Pilachowski , J. Cummings , C. I. Johnson , F. Bresolin

We present CH and CN index analysis and C and N abundance calculations based on the low-resolution blue spectra of red giant branch (RGB) stars in the Galactic globular cluster NGC 7089 (M 2). Our main goal is to investigate the C-N…

Solar and Stellar Astrophysics · Physics 2015-06-11 C. Lardo , E. Pancino , A Mucciarelli , A. P. Milone

We present an analysis of FLAMES-Giraffe spectra for several bright giants in NGC 6441, to investigate the presence and extent of the Na-O anticorrelation in this anomalous globular cluster. The field of NGC 6441 is very crowded, with…

This work aims to analyze some of the polluters proposed in the self-enrichment scenarios put forward to explain the multiple populations in globular clusters (GCs), extending previous studies. Three scenarios with different polluter stars…

Solar and Stellar Astrophysics · Physics 2024-10-09 Ricardo J. Vaca , Ivan Cabrera-Ziri , Gladis Magris C. , Nate Bastian , Maurizio Salaris

It is generally accepted today that Galactic globular clusters (GGCs) consist of at least two generations of stars that are different in their chemical composition and perhaps age. However, knowledge about the kinematical properties of…

Solar and Stellar Astrophysics · Physics 2014-09-05 A. Kucinskas , V. Dobrovolskas , P. Bonifacio

We present the abundance analysis for a sample of 17 red giant branch stars in the metal-poor globular cluster M28 based on high resolution spectra. This is the first extensive spectroscopic study of this cluster. We derive abundances of O,…

Astrophysics of Galaxies · Physics 2016-10-12 S. Villanova , C. Moni Bidin , F. Mauro , C. Munoz , L. Monaco

We use accurate radial velocities for 1981 member stars in 20 Galactic globular clusters, collected within our large survey aimed at the analysis of the Na-O anti-correlation, to study the internal kinematics of the clusters. We performed…

Astrophysics of Galaxies · Physics 2015-06-03 M. Bellazzini , A. Bragaglia , E. Carretta , R. G. Gratton , S. Lucatello , G. Catanzaro , F. Leone

Context. Globular clusters are considered key objects for understanding the formation and evolution of the Milky Way. In this sense, their characterisation in terms of their chemical and orbital parameters can provide constraints to the…

Astrophysics of Galaxies · Physics 2024-02-12 J. Schiappacasse-Ulloa , S. Lucatello , G. Cescutti , E. Carretta

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

Globular Clusters (GCs) exhibit star-to-star variations in specific elements (e.g., He, C, N, O, Na, Al) that bare the hallmark of high temperature H burning. These abundance variations can be observed spectroscopically and also…

Solar and Stellar Astrophysics · Physics 2018-10-17 Nate Bastian , Carmela Lardo

The aim of the present work is to determine accurate metallicities for a group of red giant branch stars in the field of the bulge Globular Cluster NGC 6441. This is the third paper of a series resulting from a large project aimed at…

Astrophysics · Physics 2009-11-11 R. G. Gratton , S. Lucatello , A. Bragaglia , E. Carretta , Y. Momany , E. Pancino , E. Valenti

Globular clusters exhibit star-to-star chemical variations, traceable through both photometric and spectroscopic data. In this study, we investigate chemical variations in the globular cluster NGC104 (47Tucanae), aiming to trace multiple…

Astrophysics of Galaxies · Physics 2025-06-16 S. Villanova , L. Monaco , Y. Momany , A. Plotnikova , I. Ordenes

NGC 4833 is a metal-poor Galactic globular cluster (GC) whose multiple stellar populations present an extreme chemical composition. The Na-O anti-correlation is quite extended, which is in agreement with the long tail on the blue horizontal…

Solar and Stellar Astrophysics · Physics 2021-06-02 Eugenio Carretta

It has been suggested that IC4499 is one of the very few old globulars to not host multiple populations with light-element variations. To follow-up on this very interesting result, here we make use of accurate HST photometry and FLAMES@VLT…

Solar and Stellar Astrophysics · Physics 2018-10-24 E. Dalessandro , C. Lardo , M. Cadelano , S. Saracino , N. Bastian , A. Mucciarelli , M. Salaris , P. Stetson , E. Pancino

We have calculated synthetic spectra for typical chemical element mixtures (i.e., a standard alpha-enhanced distribution, and distributions displaying CN and ONa anticorrelations) found in the various subpopulations harboured by Galactic…

Solar and Stellar Astrophysics · Physics 2015-05-27 L. Sbordone , M. Salaris , A. Weiss , S. Cassisi

We follow the static abundance profiles of the C, N, O, Ne, Na, Mg, and Al isotopes around the hydrogen-burning shell (H shell) of globular cluster red-giant-branch (RGB) stellar models in order to study the observed abundance anomolies…

Astrophysics · Physics 2009-10-30 Robert M. Cavallo , Allen V. Sweigart , Roger A. Bell