English
Related papers

Related papers: Lithium observations in 47 Tuc

200 papers

We determined the silicon abundances of 253 metal-poor stars in the metallicity range $-4<\mathrm{[Fe/H]} <-1.5$, based on non-local thermodynamic equilibrium (NLTE) line formation calculations of neutral silicon and high-resolution spectra…

Solar and Stellar Astrophysics · Physics 2015-05-19 L. Zhang , T. Karlsson , N. Christlieb , A. J. Korn , P. S. Barklem , G. Zhao

This work presents a homogeneous determination of lithium abundances in a large sample of giant-planet hosting stars (N=117), and a control sample of disk stars without detected planets (N=145). The lithium abundances were derived using a…

Solar and Stellar Astrophysics · Physics 2010-11-04 L. Ghezzi , K. Cunha , V. V. Smith , R. de la Reza

Context: A small number of K-type giants on the red giant branch (RGB) is known to be very rich in lithium (Li). This fact is not accounted for by standard stellar evolution theory. The exact phase and mechanism of Li enrichment is still a…

Solar and Stellar Astrophysics · Physics 2015-06-03 Thomas Lebzelter , Stefan Uttenthaler , Maurizio Busso , Mathias Schultheis , Bernhard Aringer

Lithium-rich giant stars are rare and their existence challenges our understanding of stellar structure and evolution. We profit from the high-quality sample gathered with HARPS and UVES, in order to search for Li-rich giants and to…

Solar and Stellar Astrophysics · Physics 2023-06-21 M. Tsantaki , E. Delgado-Mena , D. Bossini , S. G. Sousa , E. Pancino , J. H. C. Martins

Precision UBVRI photometry of NGC 7789 is combined with Gaia data to map reddening variations across the cluster face. HYDRA spectra, Gaia astrometry, and isochrone fitting constrain the absolute reddening, apparent modulus, and age to…

We identify 6 early M-dwarfs, in 3 open clusters (NGC 2451a, Blanco 1 and NGC 2516) at ages of 50-200 Myr, that are anomalously enriched in lithium compared with Li-depleted siblings of similar spectral type. The Li-rich outliers represent…

Solar and Stellar Astrophysics · Physics 2026-05-26 R. D. Jeffries , R. J. Jackson , I. Baraffe

Lithium abundances in a selected sample of halo stars have been revised by using new accurate Teff. From 41 plateau stars we found no evidence for intrinsic dispersion, a tiny trend with Teff and no trend with [Fe/H]. These results argue…

Astrophysics · Physics 2007-05-23 Piercarlo Bonifacio , Paolo Molaro

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

We examine outstanding issues in the analysis and interpretation of the halo Li plateau. We show that the majority of very Li-poor halo Li-plateau stars (5 out of 8) have high projected rotation velocities vsini between 4.7 and 10.4 km…

Astrophysics · Physics 2007-05-23 Sean G. Ryan , Lisa Elliott

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 revisit large spectroscopic data sets for field stars from the literature to derive the upper Li envelope in the high metallicity regime in our Galaxy. We take advantage of Gaia EDR3 data and state-of-the-art stellar models to precisely…

Astrophysics of Galaxies · Physics 2021-05-12 C. Charbonnel , S. Borisov , N. Prantzos , P. De Laverny

We determined abundances of Mg and K in the atmospheres of 53 (Mg) and 75 (K) turn-off (TO) stars of the Galactic globular cluster 47 Tuc. The obtained abundances, together with those of Li, O, and Na, were used to search for possible…

Solar and Stellar Astrophysics · Physics 2018-04-27 A. Černiauskas , A. Kučinskas , J. Klevas , V. Dobrovolskas , S. Korotin , P. Bonifacio , H. -G. Ludwig , E. Caffau , M. Steffen

We have serendipitously identified the first lithium-rich giant star located close to the red giant branch bump in a globular cluster. Through intermediate-resolution FLAMES spectra we derived a lithium abundance of A(Li)=2.55 (assuming…

We present lithium abundances for 119 main-sequence stars in the old open cluster NGC 188 (age = 6.3 Gyr), using high-resolution, high signal-to-noise ratio spectra from WIYN/Hydra. We observe the stars over multiple nights and measure…

Solar and Stellar Astrophysics · Physics 2025-09-19 Qinghui Sun , Constantine P. Deliyannis , Bruce A. Twarog , Barbara J. Anthony-Twarog

We have determined Li abundances for 11 G-type stars in the 6-8 Gyr old open cluster NGC 188. These data significantly enlarge the number of cluster stars with Li measurements, allowing us to extend the investigation of Li depletion in open…

Astrophysics · Physics 2008-11-26 Sofia Randich , Paola Sestito , Roberto Pallavicini

Lithium rich stars in globular clusters are rare. In fact, only 14 have been found so far, in different evolutionary phases from dwarfs to giants. Different mechanisms have been proposed to explain this enhancement, but it is still an open…

With an aim to shed light on the origin of Li anomaly observed in a small fraction of red giants, we carried out a spectroscopic study on the observational characteristics of selected 20 bright Li-rich giants, in comparison with a large…

Solar and Stellar Astrophysics · Physics 2017-09-20 Yoichi Takeda , Akito Tajitsu

Recently, we studied the chemical evolution of lithium in the thin disc of the Milky Way. We found that the best agreement with the observed Li abundances in the thin disc is obtained considering novae as the main source of lithium. We…

Solar and Stellar Astrophysics · Physics 2020-04-15 G. Cescutti , P. Molaro , X. Fu

Lithium is an important element for the understanding of ultracool dwarfs because it is lost to fusion at masses above $\sim 68\, M_{\rm J}$. Hence, the presence or absence of atomic Li has served as an indicator of the nearby H-burning…

Solar and Stellar Astrophysics · Physics 2021-09-29 Ehsan Gharib-Nezhad , Mark S. Marley , Natasha E. Batalha , Channon Visscher , Richard S. Freedman , Roxana E. Lupu

We aim to constrain the mixing processes in low-mass stars by investigating the behaviour of the Li surface abundance after the main sequence. We take advantage of the data from the sixth internal data release of Gaia-ESO, idr6, and from…