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Related papers: Lithium-Rich Giants in Globular Clusters

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Lithium-rich red giants have been a long-standing mystery in stellar astrophysics. A leading theory to explain these chemically peculiar and rare objects is interactions with a close companion. To investigate their companion fraction, we…

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

Galactic globular clusters (GCs) are known to host multiple stellar populations: a first generation with a chemical pattern typical of halo field stars and a second generation (SG) enriched in Na and Al and depleted in O and Mg. Both…

Solar and Stellar Astrophysics · Physics 2015-12-09 D. A. Garcia-Hernandez , Sz. Meszaros , M. Monelli , S. Cassisi , P. B. Stetson , O. Zamora , M. Shetrone , S. Lucatello

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

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

A sample of AGB/RGB stars with an excess of Li abundances is considered in order to estimate their mass loss rates. Our method is based on a correlation between the Li abundances and the stellar luminosity, using a modified version of…

Solar and Stellar Astrophysics · Physics 2018-06-13 W. J. Maciel , R. D. D. Costa

We have analyzed high-dispersion spectra in the Li 6708 Angstrom region for 167 stars within the anticenter cluster, NGC 2204. From 105 probable members, abundance analysis of 45 evolved stars produces [Fe/H] = -0.40 +/- 0.12, [Si/Fe] =…

Solar and Stellar Astrophysics · Physics 2024-06-28 Barbara J. Anthony-Twarog , Constantine P. Deliyannis , Aaron Steinhauer , Qinghui Sun , Bruce A. Twarog

The discrepancy between cosmological Li abundance inferred from Population II dwarf stars and that derived from WMAP/BBNS is still far from being solved.We investigated, as an alternative route, the use of Li abundances in Population II…

Solar and Stellar Astrophysics · Physics 2015-05-30 A. Mucciarelli , M. Salaris , P. Bonifacio

A Li-rich red giant star (2M19411367+4003382) recently discovered in the direction of NGC 6819 belongs to the rare subset of Li-rich stars that have not yet evolved to the luminosity bump, an evolutionary stage where models predict Li can…

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…

The vast majority of stars with mass similar to the Sun are expected to only destroy lithium over the course of their lives, via low-temperature nuclear burning. This has now been supported by observations of hundreds of thousands of red…

Solar and Stellar Astrophysics · Physics 2020-07-15 Yerra Bharat Kumar , Bacham E. Reddy , Simon W. Campbell , Sunayana Maben , Gang Zhao , Yuan-Sen Ting

We present the results of mid-resolution spectroscopy in the LiI 6708 AA spectral region of Asymptotic Giant Branch (AGB) stars belonging to young open clusters of the Large Magellanic Cloud. Most stars belong to the clusters NGC 1866 and…

Astrophysics · Physics 2009-11-07 C. Maceroni , V. testa , B. Plez , P. Garcia Lario , F. D'Antona

Although not predicted by standard stellar evolution, the surface abundance of light elements, such as lithium (Li), carbon, and nitrogen, changes during the red giant branch (RGB) as a result of extra-mixing. This is associated usually…

Solar and Stellar Astrophysics · Physics 2023-02-08 Claudia Aguilera-Gómez , Matías I. Jones , Julio Chanamé

Li abundances in the bulk of low-mass metal-poor stars are well reproduced by stellar evolution models adopting a constant initial abundance. However, a small number of stars have exceptionally high Li abundances, for which no convincing…

Solar and Stellar Astrophysics · Physics 2018-01-31 Haining Li , Wako Aoki , Tadafumi Matsuno , Yerra Bharat Kumar , Jianrong Shi , Takuma Suda , Gang Zhao

We present high-resolution (R~60,000) optical spectra of a carefully selected sample of heavily obscured and presumably massive O-rich Asymptotic Giant Branch (AGB) stars in the Magellanic Clouds (MCs). We report the discovery of strong Rb…

Solar and Stellar Astrophysics · Physics 2014-11-20 D. A. Garcia-Hernandez , A. Manchado , D. L. Lambert , B. Plez , P. Garcia-Lario , F. D'Antona , M. Lugaro , A. I. Karakas , M. van Raai

Lithium is a fragile but crucial chemical element in the universe, exhibits interesting and complex behaviors. Thanks to the massive spectroscopic data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)…

The lithium abundances for 378 G/K giants are derived with non-LTE correction considered. Among these, there are 23 stars that host planetary systems. The lithium abundance is investigated, as a function of metallicity, effective…

Solar and Stellar Astrophysics · Physics 2015-06-19 Y. J. Liu , K. F. Tan , L. Wang , G. Zhao , Bun'ei Sato , Y. Takeda , H. N. Li

The cosmological Li problem is the observed discrepancy between Li abundance, A(Li), measured in Galactic dwarf, old and metal-poor stars (traditionally assumed to be equal to the initial value A(Li)_0), and that predicted by standard Big…

Solar and Stellar Astrophysics · Physics 2015-06-22 A. Mucciarelli , M. Salaris , P. Bonifacio , L. Monaco , S. Villanova

Standard stellar evolution model predicts a severe depletion of lithium (Li) abundance during the first dredge-up process (FDU). Yet a small fraction of giant stars are still found to preserve a considerable amount of Li in their…

During Big Bang nucleosynthesis (BBN) in the first 15 minutes of the Universe some $^7$Li was created along with isotopes of H and He. The determination of that primordial value of Li can help constrain the conditions at that time. The…

Solar and Stellar Astrophysics · Physics 2024-06-26 Ann Merchant Boesgaard , Constantine P. Deliyannis
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