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Related papers: Lithium-rich giants in the Galactic thick disk

200 papers

We report the first high resolution, detailed abundances of 21 elements for giants in the Galactic bulge/bar within $1^\circ$ of the Galactic plane, where high extinction has rendered such studies challenging. Our high S/N and…

Aims. This study aims to determine the level and constancy of the Spite plateau as definitively as possible from homogeneous high-quality VLT-UVES spectra of 19 of the most metal-poor dwarf stars known. Methods. Our high-resolution (R ~…

The light element lithium is formed by nucleosynthesis during the Big Bang. Its abundance can help to define the parameters of the early universe. To find this primordial value, it is necessary to determine Li abundances in the oldest stars…

Solar and Stellar Astrophysics · Physics 2023-07-28 Ann Merchant Boesgaard , Constantine P. Deliyannis

Aims. We present a spectroscopic analysis of a sample of evolved stars in M67 (turn-off, subgiant and giant stars) in order to bring observational constraints to evolutionary models taking into account non-standard transport processes.…

Solar and Stellar Astrophysics · Physics 2015-03-17 B. L. Canto Martins , A. Lèbre , A. Palacios , P. de Laverny , O. Richard , C. H. F. Melo , J. D. do Nascimento , J. R. De Medeiros

The nuclei of the lithium isotopes are fragile, easily destroyed, so that, at variance with most of the other elements, they cannot be formed in stars through steady hydrostatic nucleosynthesis. The 7Li isotope is synthesized during…

Astrophysics of Galaxies · Physics 2015-05-18 Monique Spite , François Spite

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…

Lithium is a fundamental element for studying the mixing mechanisms acting in the stellar interiors, for understanding the chemical evolution of the Galaxy and the Big Bang nucleosynthesis. The study of Li in stars of open clusters…

Solar and Stellar Astrophysics · Physics 2015-06-15 P. Francois , L. Pasquini , K. Biazzo , P. Bonifacio , R. Palsa

We have studied 23 very metal-poor field turnoff stars, specifically chosen to enable a precise measurement of the dispersion in the lithium abundance of the Spite Li plateau. We concentrated on stars having a narrow range of effective…

Astrophysics · Physics 2009-10-31 Sean G. Ryan , John E. Norris , Timothy C. Beers

[Abridged abstract] We have performed an abundance analysis for 176 F- and G- dwarfs of the Galactic thick disk component. Using accurate radial velocities combined with $Hipparcos$ astrometry, kinematics (U, V, and W) and Galactic orbital…

Astrophysics · Physics 2009-11-13 Bacham E. Reddy , David L. Lambert , Carlos Allende Prieto

We present elemental abundances for eight unevolved extremely metal-poor stars with $T_{\rm eff}>5500\,\mathrm{K}$, among which seven have $[\mathrm{Fe/H}]<-3.5$. The sample is selected from the Sloan Digital Sky Survey / Sloan Extension…

Solar and Stellar Astrophysics · Physics 2017-07-26 Tadafumi Matsuno , Wako Aoki , Timothy C. Beers , Young Sun Lee , Satoshi Honda

Recent spectroscopic explorations of large Galactic stellar samples stars have revealed the existence of red giants with [$\alpha$/Fe] ratios that are anomalously high, given their relatively young ages. We revisit the GALAH DR3 survey to…

Solar and Stellar Astrophysics · Physics 2022-12-21 S. Borisov , N. Prantzos , C. Charbonnel

Precise Li abundances are determined for 54 giant stars mostly evolving across the Hertzsprung gap. We combine these data with rotational velocity and with information related to the deepening of the convective zone of the stars to analyse…

Astrophysics · Physics 2009-11-10 P. de Laverny , J. D. Jr do Nascimento , A. Lebre , J. R. De Medeiros

We have refined the estimate of the primordial level of $^7$Li abundance to an accuracy better than 10%, based on high-precision Li abundances for metal-poor halo stars, and a recent model of post-BBN (Big Bang Nucleosynthesis) chemical…

Astrophysics · Physics 2009-10-31 Takeru Ken Suzuki , Yuzuru Yoshii , Timothy C. Beers

The abundances of iron and oxygen are homogeneously determined in a sample of 523 nearby (d<150 pc) FGK disk and halo stars with metallicities in the range -1.5<[Fe/H]<0.5. The oxygen abundances were inferred from a restricted non-LTE…

Astrophysics · Physics 2009-11-13 I. Ramirez , C. Allende Prieto , D. L. Lambert

The determination of Li and proton-capture element abundances in globular cluster (GC) giants allows us to constrain several key questions on the multiple population scenarios in GCs, from formation and early evolution, to pollution and…

Solar and Stellar Astrophysics · Physics 2015-05-19 Valentina D'Orazi , Anna F. Marino

Abundances of lithium, carbon, and oxygen have been derived using spectral synthesis for a sample of 249 bright F, G, and K Northern Hemisphere dwarf stars from the high-resolution spectra acquired with the VUES spectrograph at the Moletai…

Observations of low-metallicity halo stars have revealed a puzzling result: the abundance of \li7 in these stars is at least three times lower than their predicted primordial abundance. It is unclear whether the cause of this disagreement…

Astrophysics of Galaxies · Physics 2015-06-12 Tijana Prodanovic , Tamara Bogdanovic , Dejan Urosevic

The determination of accurate stellar parameters of giant stars is essential for our understanding of such stars in general and as exoplanet host stars in particular. Precise stellar masses are vital for determining the lower mass limit of…

Solar and Stellar Astrophysics · Physics 2018-08-15 Stephan Stock , Sabine Reffert , Andreas Quirrenbach

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

Nineteen carbon stars that show lithium enrichment in their atmospheres have been discovered among a sample of 674 carbon stars in the Large Magellanic Cloud. Six of the Li-rich carbon stars are of J-type, i.e. with strong 13C isotopic…

Astrophysics · Physics 2011-03-10 D. Hatzidimitriou , D. H. Morgan , R. D. Cannon , B. F. W. Croke