Lithium Abundances of Extremely Metal-Poor Turnoff Stars

@article{Aoki2009LithiumAO,
  title={Lithium Abundances of Extremely Metal-Poor Turnoff Stars},
  author={Wako Aoki and Paul S. Barklem and Timothy C. Beers and Norbert Christlieb and S. Inoue and Ana Elia Garc{\'i}a P{\'e}rez and John E. Norris and Daniela Carollo},
  journal={The Astrophysical Journal},
  year={2009},
  volume={698},
  pages={1803-1812}
}
We have determined Li abundances for eleven metal-poor turnoff stars, among which eight have [Fe/H] < -3, based on LTE analyses of high-resolution spectra obtained with the High Dispersion Spectrograph on the Subaru Telescope. The Li abundances for four of these eight stars are determined for the first time by this study. Effective temperatures are determined by a profile analysis of H alpha and H beta. While seven stars have Li abundances as high as the Spite Plateau value, the remaining four… Expand
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References

SHOWING 1-10 OF 52 REFERENCES
Lithium and lithium depletion in halo stars on extreme orbits
We have determined Li abundances in 55 dwarfs and subgiants that are metal-poor (-3.6 < [Fe/H] < -0.7) and have extreme orbital kinematics. Our purpose is to examine the Li abundance in the LiExpand
SPECTROSCOPIC STUDIES OF VERY METAL-POOR STARS WITH THE SUBARU HIGH DISPERSION SPECTROGRAPH. III. LIGHT NEUTRON-CAPTURE ELEMENTS
Elemental abundance measurements have been obtained for a sample of 18 very metal-poor stars using spectra obtained with the Subaru Telescope High Dispersion Spectrograph. Seventeen stars, amongExpand
Lithium isotopic abundances in metal-poor halo stars
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 one-dimensional, non-LTEExpand
Variations in the lithium abundances of turn off stars in the globular cluster 47 Tucanae
Aims. Our aim is to determine Li abundances in turn off stars of the globular cluster 47 Tuc and test theories about Li variations among turn off stars. Methods. We make use of high resolution (R ∼Expand
NLTE determination of the sodium abundance in a homogeneous sample of extremely metal-poor stars
Abundance ratios in extremely metal-poor (EMP) stars are a good indication of the chemical composition of the gas in the earliest phases of the Galaxy evolution. It had been found from an LTEExpand
Isotopic Lithium Abundances in Nine Halo Stars
High-resolution echelle spectra of the 6707.8 ? Li I absorption line in spectra of metal-poor halo dwarfs and subgiants are analyzed for the isotopic fractions of 6Li and 7Li. Positive detections ofExpand
Li in NGC 6752 and the formation of globular clusters
Li abundances for 9 Turn-off (TO) stars of the intermediate metallicity cluster ([Fe/H] =-1.4) NGC 6752 are presented. The cluster is known to show abundance anomalies and anticorrelations observedExpand
Extremely Metal-poor Stars. VII. The Most Metal-poor Dwarf, CS 22876-032
We report high-resolution, high signal-to-noise observations of the extremely metal-poor double-lined spectroscopic binary CS 22876-032. The system has a long period: P = 424.7 ± 0.6 days. ItExpand
Rapid Rotation of Ultra-Li-depleted Halo Stars and Their Association with Blue Stragglers
Observations of 18 halo main-sequence turnoff stars, four of which are extremely deficient in Li, show that three of the Li-poor ones have substantial line broadening. We attribute this to stellarExpand
Lithium abundance at the formation of the Galaxy
The observed abundance of lithium in population I stars (young stars)1 seems to have been stable during the past 5 × 109 yr (ref. 2). This stability has been used previously1,3 to estimate theExpand
...
1
2
3
4
5
...