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Two problems are discussed here. The first one is the 0.4 dex discrepancy between the 7Li abundance derived from the spectra of metal-poor halo stars on the one hand, and from Big Bang nucleosynthesis, based on the cosmological parameters…

The main goal of this work is to evaluate the correlation between Li abundance, age, and mass. Using high-quality ESO/HARPS data (R $\simeq$ 115 000; 270 $\leq$ SNR $\leq$ 1000), we measured Li abundances via spectral synthesis of the…

Solar and Stellar Astrophysics · Physics 2023-09-15 Anne Rathsam , Jorge Meléndez , Gabriela Carvalho Silva

We have measured the Li abundance of 18 stars with -2 <~ [Fe/H] ~< -1 and 6000 K <~ Teff <~ 6400 K, a parameter range that was poorly represented in previous studies. We examine the Galactic chemical evolution (GCE) of this element,…

We present an elemental abundance analysis for four newly discovered ultra metal-poor stars from the Hamburg/ESO survey, with $\mathrm{[Fe/H]}\leq-4$. Based on high-resolution, high signal-to-noise spectra, we derive abundances for 17…

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

Planet engulfment has been identified as one of the mechanisms for enhancing lithium abundance in stars. However, comprehensive investigations into lithium signatures following such events remain limited. Stars born together, sharing a…

We present a study of the evolutionary state of a few lithium-rich giant stars based on the Gaia DR2 parallaxes and photometry. We also investigate the chromospheric activity, the presence of a surface magnetic field, and the radial…

Solar and Stellar Astrophysics · Physics 2020-09-09 B. F. O. Gonçalves , J. S. da Costa , L. de Almeida , M. Castro , J. -D. do Nascimento

Lithium abundances have been determined in more than 100 metal-poor halo stars both in the field and in clusters. From these data we find trends of Li with both temperature and metallicity and a real dispersion in Li abundances in the Spite…

Astrophysics · Physics 2009-11-11 Ann Merchant Boesgaard , Megan C. Novicki , Alex Stephens

Lithium abundances determined by spectral synthesis from both the 6708A resonance line and the 6104 subordinate line are reported for 11 late-type Pleiades stars, including spectra previously analysed by Russell (1996). We report a 0.7 dex…

Astrophysics · Physics 2009-11-07 A. Ford , J. Jeffries , B. Smalley

We have studied a sample of 11 blue, luminous, metal-poor galaxies at redshift 0.744 < z < 0.835 from the DEEP2 redshift survey. They were selected by the presence of the [OIII]4363 auroral line and the [OII]3726,3729 doublet together with…

Astrophysics of Galaxies · Physics 2014-12-15 J. M. Perez-Martinez

The aim of the project is to search for lithium in absorption at 6707.8 Angstroms to constrain the nature and the mass of the brightest low-metallicity L-type dwarfs (refered to as L subdwarfs) identified in large-scale surveys. We obtained…

Solar and Stellar Astrophysics · Physics 2015-07-01 N. Lodieu , A. J. Burgasser , Y. Pavlenko , R. Rebolo

The aims of this paper are: 1) to revisit the Tc content of a sample of oxygen-rich asymptotic giant branch (AGB) variables and 2) to increase the number of such stars for which the Li abundance has been measured to provide constraints on…

Solar and Stellar Astrophysics · Physics 2015-05-14 Stefan Uttenthaler , Thomas Lebzelter

We report the discovery of a peculiar set of old super-metal-rich dwarf stars with orbits of low eccentricity that reach a maximum height from the Galactic plane between $\sim$ 0.5-1.5 kpc observed by the \emph{Gaia}-ESO Survey. These stars…

Solar and Stellar Astrophysics · Physics 2025-01-29 M. L. L. Dantas , R. Smiljanic , R. Boesso , H. Rocha-Pinto , L. Magrini , G. Guiglion , D. Romano

Accurately known stellar lithium abundances may be used to shed light on a variety of astrophysical phenomena such as Big Bang nucleosynthesis, radial migration, ages of stars and stellar clusters, and planet engulfment events. We present a…

Solar and Stellar Astrophysics · Physics 2020-10-30 E. Wang , T. Nordlander , M. Asplund , A. M. Amarsi , K. Lind , Y. Zhou

The role of novae as producers of galactic lithium has been suggested since the 1970s, and it has been reconsidered recently with the detection of $^7$Be in their outbursts. At the same time, stellar models are moving forward to comprehend…

Astrophysics of Galaxies · Physics 2025-11-19 C. T. Nguyen , G. Cescutti , F. Matteucci , F. Rizzuti , A. Mucciarelli , D. Romano , L. Magrini , A. J. Korn , A. Bressan , L. Girardi

The lines of lithium at 6708 A, and 6103 A, are analyzed in high resolution spectra of some sharp-lined and slowly rotating roAp stars. Three spectral synthesis codes - STARSP, ZEEMAN2 and SYNTHM were used. New lines of the rare earth…

I summarize the results of 15 years of research on the surface abundances of stars in globular clusters. Globular-cluster stars afford a unique view of the physical processes that shape the surface abundances of stars on and beyond the…

Solar and Stellar Astrophysics · Physics 2021-11-02 A. J. Korn

A discrepancy has emerged between the cosmic lithium abundance inferred by the WMAP satellite measurement coupled with the prediction of the standard big-bang nucleosynthesis theory, and the constant Li abundance measured in metal-poor halo…

Astrophysics of Galaxies · Physics 2015-05-19 L. Monaco , P. Bonifacio , L. Sbordone , S. Villanova , E. Pancino

Convergent lines of evidence suggest that globular clusters host multiple stellar populations. It appears that they experience at least two episodes of star formation whereby a fraction of first-generation stars contribute astrated ejecta…

Globular cluster stars show chemical abundance patterns typical of hot-CNO processing. Lithium is easily destroyed by proton capture in stellar environments, so its abundance may be crucial to discriminate among different models proposed to…

Astrophysics of Galaxies · Physics 2015-06-05 F. D'Antona , A. D'Ercole , R. Carini , E. Vesperini , P. Ventura