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相关论文: Lithium Abundances in a Sample of Planet Hosting D…

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We present a series of systematic abundance measurements for 89 hot DA white dwarfs drawn from the FUSE observation archive. These stars span the temperature range ~ 20000-70000K, and form the largest sample to-date, exceeding our earlier…

太阳与恒星天体物理 · 物理学 2013-02-27 M. A. Barstow , S. L. Casewell , J. B. Holberg , J. K. Barstow

The dispersion in lithium abundance at fixed effective temperature in young cool stars like the Pleiades has proved a difficult challenge for stellar evolution theory. We propose that Li abundances relative to a mean temperature trend,…

天体物理学 · 物理学 2009-10-31 Jeremy King , Anita Krishnamurthi , Marc H. Pinsonneault

We present stellar parameters and metallicities for 29 planet-host stars, as well as for a large volume-limited sample of 53 stars not known to be orbited by any planetary-mass companion. These stars add to the results presented in our…

天体物理学 · 物理学 2009-11-10 N. C. Santos , G. Israelian , M. Mayor , J. P. Bento , P. C. Almeida , S. G. Sousa , A. Ecuvillon

We test a scenario in which radial migration could affect the Li abundance pattern of dwarf stars in the solar neighbourhood. This may confirm that the Li abundance in these stars can not serve as a probe for the Li abundance in the…

Theoretical models predict that subgiants within a narrow mass regime can retain detectable lithium enrichment signatures from planetary engulfment. We test this prediction using TOI-5882, selected because it occupies this favorable…

Very high-quality spectra of 24 metal-poor halo dwarfs and subgiants have been acquired with ESO's VLT/UVES for the purpose of determining Li isotopic abundances. The derived 1D, non-LTE 7Li abundances from the LiI 670.8nm line reveal a…

天体物理学 · 物理学 2008-11-26 Martin Asplund , David L. Lambert , Poul Erik Nissen , Francesca Primas , Verne V. Smith

Li-rich giants serve as valuable tracers of stellar evolution and surface enrichment processes, for which a statistically large and homogeneous sample is crucial. Using the massive low-resolution ($R \sim 1800$) spectroscopic dataset from…

Based on detailed 2D radiation hydrodynamics (RHD) simulations, we have investigated the effects of photospheric temperature inhomogeneities induced by convection on spectroscopic determinations of the lithium abundance. Computations have…

天体物理学 · 物理学 2007-05-23 R. Cayrel , M. Steffen

The disagreement between theoretical predictions and observations for surface lithium abundance in stars is a long-standing problem, which indicates that the adopted physical treatment is still lacking in some points. However, thanks to the…

太阳与恒星天体物理 · 物理学 2015-06-11 E. Tognelli , S. Degl'Innocenti , P. G. Prada Moroni

We present independent and self-consistent metallicities for a sample of 807 planet-hosting stars from the California-Kepler Survey from an LTE spectroscopic analysis using a selected sample of Fe I and Fe II lines. Correlations between…

地球与行星天体物理 · 物理学 2021-10-14 Luan Ghezzi , Cintia F. Martinez , Robert F. Wilson , Katia Cunha , Verne V. Smith , Steven R. Majewski

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 report the discovery of eight lithium-rich field giants found in a high resolution spectroscopic sample of over 700 metal-poor stars ([Fe/H]<-0.5) selected from the RAVE survey. The majority of the Li-rich giants in our sample are very…

The standard model of primordial nucleosynthesis by the Big Bang as selected by the WMAP-based estimate of the baryon density ($\Omega_bh^2$) predicts an abundance of $^7$Li that is a factor of three greater than the generally reported…

天体物理学 · 物理学 2009-11-10 David L. Lambert

Spectroscopically determined Li abundances of metal-poor turn-off dwarfs are known to be nearly constant (Spite plateau), but lower than the primordial value expected from the standard cosmological model. However, abundance determination by…

太阳与恒星天体物理 · 物理学 2019-02-06 Yoichi Takeda

The surface content of lithium (Li) and beryllium (Be) in stars can reveal important information about the temperature structure and physical processes in their interior regions. This study focuses on solar-type stars with a sample that is…

太阳与恒星天体物理 · 物理学 2022-12-14 Ann Merchant Boesgaard , Constantine P. Deliyannis , Michael G. Lum , Ashley Chontos

Most Globular Clusters are believed to host a single stellar populations. They can thus be considered a good place to study the Spite plateau and probe for possible evolutionary modifications of the Li content. We want to determine the Li…

We present NLTE Li abundances for 88 stars in the metallicity range -3.5 < [Fe/H] < -1.0. The effective temperatures are based on the infrared flux method with improved E(B-V) values obtained mostly from interstellar NaI D lines. The Li…

太阳与恒星天体物理 · 物理学 2015-05-19 Jorge Melendez , Luca Casagrande , Ivan Ramirez , Martin Asplund , William Schuster

We present data for four ultra-Li-deficient, warm, halo stars. The Li deficiency of two of these is a new discovery. Three of the four stars have effective temperatures Teff ~ 6300 K, in contrast to previously known Li-deficient halo stars…

天体物理学 · 物理学 2009-10-31 Sean G. Ryan , Timothy C. Beers , Toshitaka Kajino , Katarina Rosolankova

We present Li abundances for 73 stars in the metallicity range -3.5 < [Fe/H] < -1.0 using improved IRFM temperatures (Casagrande et al. 2010) with precise E(B-V) values obtained mostly from interstellar NaI D lines, and high-quality…

太阳与恒星天体物理 · 物理学 2015-05-14 J. Melendez , L. Casagrande , I. Ramirez , M. Asplund , W. J. Schuster

We present FLAMES/GIRAFFE spectroscopy obtained at the Very Large Telescope (VLT). Using these observations we have been able for the first time to observe the Li I doublet in the Main Sequence stars of a Globular Cluster. We also observed…