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Related papers: Lithium in the Globular Cluster NGC 6397: Evidence…

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{The aim of this work is to investigate the relations between the abundances of different elements in the globular cluster M4, selected for its uniform deficiency of iron, to explore the best models explaining the pattern of these observed…

(Abridged) We contribute to our understanding of the evolution of young intermediate-mass stars by providing a comprehensive analysis of their lithium (Li) content. A sample of 71 intermediate-mass T Tauri (IMTT) and Herbig stars within the…

Globular Clusters are among the oldest objects in the Galaxy, thus their researchers are key to understanding the processes of evolution and formation that the galaxy has experienced in early stages. Spectroscopic studies allow us to carry…

Astrophysics of Galaxies · Physics 2021-03-24 Carolina Montecinos , S. Villanova , C. Muňoz , C. C. Cortés

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

We present the results of the analysis of high-resolution spectra obtained with UVES-FLAMES@VLT for six red giant branch stars in the outer-halo metal-poor ([Fe/H]I=-1.98 and [Fe/H]II=-1.83) Galactic globular cluster NGC 5694, which has…

Solar and Stellar Astrophysics · Physics 2015-06-17 A. Mucciarelli , M. Bellazzini , M. Catelan , E. Dalessandro , P. Amigo , M. Correnti , C. Cortés , V. D'Orazi

Lithium is created during the Big Bang nucleosynthesis and it is destroyed in stellar interiors at relatively low temperatures. However, it should be preserved in the stellar envelopes of unevolved stars and progressively diluted during…

Solar and Stellar Astrophysics · Physics 2020-03-02 N. Sanna , E. Franciosini , E. Pancino , A. Mucciarelli

Recent observational work by Israelian et al. has shown that sun-like planet host stars in the temperature range 5700K < Teff < 5850K have lithium abundances that are significantly lower than those observed for "single" field stars. In this…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. G. Sousa , J. Fernandes , G. Israelian , N. C. Santos

To provide an empirical calibration relation in order to convert Lick indices into abundances for the integrated light of old, simple stellar populations for a large range in the observed [Fe/H] and [alpha/Fe]. This calibration supersedes…

Astrophysics of Galaxies · Physics 2015-05-27 A. Pipino , I. J. Danziger

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 provide the whole set of Lick indices from CN1 to TiO2 of Simple Stellar Population models with, for the first time, variable element abundance ratios, [alpha/Fe]=0.0, 0.3, 0.5, [alpha/Ca]=-0.1, 0.0, 0.2, 0.5, and [alpha/N]=-0.5, 0.0.…

Astrophysics · Physics 2009-11-07 Daniel Thomas , Claudia Maraston , Ralf Bender

Recent work has used spectra of about 5000 stars in NGC 6397 that were extracted from a MUSE mosaic to determine the atmospheric parameters for these stars by fitting the spectra against the Goettingen Spectral Library. A significant change…

Solar and Stellar Astrophysics · Physics 2020-04-08 Rashi Jain , Philippe Prugniel , Lucimara Martins , Ariane Lançon

The chemical separation of Li+ ions induced by a magnetic field during the hierarchical structure formation can reduce initial Li abundances in cosmic structures. It is shown that cosmological reionization of neutral Li atoms quickly…

Solar and Stellar Astrophysics · Physics 2019-05-15 Motohiko Kusakabe , Masahiro Kawasaki

The cosmological {7Li problem consists in explaining why the primordial Li abundance, as predicted by the standard Big Bang nucleosynthesis theory with constraints from WMAP and Planck, is a factor of 3 larger than the Li abundance measured…

Astrophysics of Galaxies · Physics 2021-05-12 Francesca Matteucci , Marta Molero , David S. Aguado , Donatella Romano

Lithium is predicted, and observed, to be depleted in contracting, low-mass pre main sequence (PMS) stars. Yet these stars reach the zero age main sequence (ZAMS) with a spread in lithium abundance at a given effective temperature that is…

Solar and Stellar Astrophysics · Physics 2025-04-28 R. J. Jackson , R. D. Jeffries , E. Tognelli

Context: In order to study the evolution of Li in the Galaxy it is necessary to observe dwarf or subgiant stars. Abridged Although Li has been extensively studied in the Galactic disk and halo, to date there is only one uncertain detection…

Astrophysics of Galaxies · Physics 2015-05-20 T. Bensby , M. Asplund , J. A. Johnson , S. Feltzing , J. Meléndez , S. Dong , A. Gould , C. Han , D. Adén , S. Lucatello , A. Gal-Yam

We present evidence for globular cluster stellar debris in a dwarf galaxy system (Sagittarius: Sgr) based on an analysis of high-resolution \textit{H}-band spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE)…

NGC 362 is a non-common Type II Galactic globular cluster, showing a complex pseudo two-color diagram or 'chromosome map'. The clear separation of its stellar populations in the color-magnitude diagram and the distribution of the giant…

Astrophysics of Galaxies · Physics 2022-07-13 C. Vargas , S. Villanova , D. Geisler , C. Muñoz , L. Monaco , J. O'Connell , Ata Sarajedini

The distinction of the stellar content in globular clusters (GCs) in multiple stellar populations characterized by different amounts of proton-capture elements has been well assessed since a long time. On the other hand, the existence of…

Astrophysics of Galaxies · Physics 2025-03-19 Eugenio Carretta , Angela Bragaglia

The spectroscopic and photometric signals of the star-to-star abundance variations found in globular clusters seem to be correlated with global parameters like the cluster's metallicity, mass and age. Understanding this behaviour could…

We present a non-local thermodynamic equilibrium abundance analysis of the resonance doublet Li I at 6707.8 A for 55 Galactic F and G supergiants and bright giants. The derived lithium abundances log \epsilon(Li) may be considered in three…

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