Lithium Abundances of Extremely Metal-Poor Turn-off Stars

Abstract

We have determined Li abundances for eleven metal-poor turn-off stars, among which eight have [Fe/H]<-3, based on LTE analyses of high-resolution spectra obtained with the HDS 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 objects with [Fe/H] <-3 have A(Li)=log(Li/H)+12 ~< 2.0, confirming the existence of extremely metal-poor turn-off stars having low Li abundances, as reported by previous work. The average of the Li abundances for stars with [Fe/H]<-3 is lower by 0.2 dex than that of the stars with higher metallicity. No clear constraint on the metallicity dependence or scatter of the Li abundances is derived from our measurements for the stars with [Fe/H]<-3. Correlations of the Li abundance with effective temperatures, with abundances of Na, Mg and Sr, and with the kinematical properties are investigated, but no clear correlation is seen in the extremely metal-poor star sample.

27 pages, 6 figures, 7 tables, ApJ in press

References in corpus (14)

• Two Stellar Components in the Halo of the Milky Way
• Nucleosynthetic signatures of the first stars
• A new implementation of the infrared flux method using the 2MASS catalogue
• A probable stellar solution to the cosmological lithium discrepancy
• Atomic Diffusion and Mixing in Old Stars I. VLT/FLAMES-UVES Observations of Stars in NGC 6397
• HE 1327-2326, an unevolved star with [Fe/H]<-5.0. II. New 3D-1D corrected abundances from a VLT/UVES spectrum
• NLTE determination of the sodium abundance in a homogeneous sample of extremely metal-poor stars
• Carbon-Enhanced Metal-Poor Stars. III. Main-Sequence Turn-Off Stars from the SDSS/SEGUE Sample
• From First Stars to the Spite Plateau: a Possible Reconciliation of Halo Stars Observations with Predictions from Big Bang Nucleosynthesis
• Lithium abundances of halo dwarfs based on excitation temperature. I. LTE
• Broadband UBVRI Photometry of Horizontal-Branch and Metal-Poor Candidates from the HK and Hamburg/ESO Surveys. I
• Non-LTE Balmer line formation in late-type spectra: Effects of atomic processes involving hydrogen atoms
• First Stars XI. Chemical composition of the extremely metal-poor dwarfs in the binary CS 22876--032
• Variations in the lithium abundances of turn off stars in the globular cluster 47 Tuc

Cited by in corpus (112)

• Big Bang Nucleosynthesis: 2015
• An absolutely calibrated effective temperature scale from the InfraRed Flux Method
• One percent determination of the primordial deuterium abundance
• Near-Field Cosmology with Metal-Poor Stars
• A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
• The Primordial Lithium Problem
• Precision big bang nucleosynthesis with improved Helium-4 predictions
• Signatures of intrinsic Li depletion and Li-Na anti-correlation in the metal-poor globular cluster NGC6397
• The metal-poor end of the Spite plateau. 1: Stellar parameters, metallicities and lithium abundances
• Big Bang Nucleosynthesis as a Probe of New Physics
• TOPoS: II. On the bimodality of carbon abundance in CEMP stars. Implications on the early chemical evolution of galaxies
• High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE: I. Atmospheric Parameters and Chemical Compositions
• Chemical abundances of the Milky Way thick disk and stellar halo II.: sodium, iron-peak and neutron-capture elements
• Abundance Profiling of Extremely Metal-Poor Stars and Supernova Properties in the Early Universe
• Observational evidence for a broken Li Spite plateau and mass-dependent Li depletion
• Neutrinos And Big Bang Nucleosynthesis
• The primordial deuterium abundance of the most metal-poor damped Lyman-alpha system
• Four-hundred Very Metal-Poor Stars Studied with LAMOST and Subaru. II. Elemental abundances
• The role of binaries in the enrichment of the early Galactic halo. II. Carbon-Enhanced Metal-Poor Stars - CEMP-no stars
• Chemical Abundances of the Milky Way Thick Disk and Stellar Halo I.: Implications of [alpha/Fe] for Star Formation Histories in Their Progenitors
• The PHLEK Survey: A New Determination of the Primordial Helium Abundance
• Lithium abundance in the globular cluster M4: from the Turn-Off to the RGB Bump
• Metal-Poor Lithium-Rich Giants in the Radial Velocity Experiment Survey
• Are There Any Stars Lacking Neutron-Capture Elements? Evidence from Strontium and Barium
• The Most Metal-Poor Stars. I. Discovery, Data, and Atmospheric Parameters
• TOPoS: IV. Chemical abundances from high-resolution observations of seven EMP stars
• The Pristine Survey IV: Approaching the Galactic metallicity floor with the discovery of an ultra metal-poor star
• Lithium abundances in CEMP stars
• Chemical abundances of distant extremely metal-poor unevolved stars
• Rotation and Internal Structure of Population III Protostars
• Cosmological Constraints on Decoupled Dark Photons and Dark Higgs
• Updated BBN constraints on electromagnetic decays of MeV-scale particles
• Metastable GeV-scale particles as a solution to the cosmological lithium problem
• Back to the Lithium Plateau with J0023+0307 with [Fe/H]<-6
• High-resolution spectroscopic studies of ultra metal-poor stars found in LAMOST survey
• Exploring the production and depletion of lithium in the Milky Way stellar disk
• Chemical Abundance Signature of J0023+0307 -- A Second-Generation Main-Sequence Star with [Fe/H]<-6
• The solar, exoplanet and cosmological lithium problems
• Giants reveal what dwarfs conceal: Li abundance in lower RGB stars as diagnostic of the primordial Li
• Atomic diffusion and mixing in old stars VI: The lithium content of M30
• Modified big bang nucleosynthesis with non-standard neutron sources
• On Possible Variation in the Cosmological Baryon Fraction
• Nuclear Reaction Uncertainties, Massive Gravitino Decays and the Cosmological Lithium Problem
• Chemical Abundances of the Outer Halo Stars in the Milky Way
• Enrichment in r-process elements from multiple distinct events in the early Draco dwarf spheroidal galaxy
• The stellar content of the Hamburg/ESO survey VI. The metallicity distribution of main-sequence turnoff stars in the Galactic halo
• High-resolution spectroscopy of extremely metal-poor stars from SDSS/SEGUE. III. Unevolved Stars with $[Fe/H]\lesssim -3.5$
• Neutron Star Mergers Are the Dominant Source of the r-process in the Early Evolution of Dwarf Galaxies
• Primordial $\alpha +d\to {}^6\mathrm{Li}+\gamma$ reaction and second Lithium puzzle
• The S2 Stream: the shreds of a primitive dwarf galaxy
• 6Li/7Li estimates for metal-poor stars
• Two distinct halo populations in the solar neighborhood. IV. Lithium abundances
• Big-bang nucleosynthesis with sub-GeV massive decaying particles
• Gravitino Decays and the Cosmological Lithium Problem in Light of the LHC Higgs and Supersymmetry Searches
• Chemical Feature of Eu abundance in the Draco dwarf spheroidal galaxy
• The barium isotopic fractions in five metal-poor stars
• Revised Big Bang Nucleosynthesis with long-lived negatively charged massive particles: updated recombination rates, primordial 9Be nucleosynthesis, and impact of new 6Li limits
• General limit on the relation between abundances of D and ${}^7$Li in big bang nucleosynthesis with nucleon injections
• Chemical Compositions of Kinematically Selected Outer Halo Stars
• Supernova Neutrino Process of Li and B Revisited
• Effects of Long-lived 10 MeV Scale Sterile Neutrino on Primordial Elemental Abundances and Effective Neutrino Number
• Lithium in CEMP-no stars: A new constraint on the lithium depletion mechanism in the early universe
• Discovery of a thin lithium plateau among metal-poor red giant branch stars
• Diversity of Abundance Patterns of Light Neutron-capture Elements in Very-metal-poor Stars
• The cosmological Lithium problem outside the Galaxy: the Sagittarius globular cluster M54
• New results on catalyzed BBN with a long-lived negatively-charged massive particle
• Examination of the mass-dependent Li depletion hypothesis by the Li abundances of the very metal-poor double-lined spectroscopic binary G166-45
• Destruction of 7Be in big bang nucleosynthesis via long-lived sub-strongly interacting massive particles as a solution to the Li problem
• Enrichment of Strontium in Dwarf Galaxies
• High Resolution Optical Spectroscopy of Stars in the Sylgr Stellar Stream
• Big-bang nucleosynthesis with a long-lived charged massive particle including ${}^4$He spallation processes
• Review on Effects of Long-lived Negatively Charged Massive Particles on Big Bang Nucleosynthesis
• Optical high-resolution spectroscopy of 14 young $\alpha$-rich stars
• Lithium abundance in a turnoff halo star on an extreme orbit
• Non-Gaussian Error Distribution of ${}^7\mathrm{Li}$ Abundance Measurements
• Population II stars and the Spite plateau; Stellar evolution models with mass loss
• Lithium abundances of halo dwarfs based on excitation temperatures. II. NLTE
• Roles of ${}^7$Be$(n,p{)}^7$Li resonances in big bang nucleosynthesis with time-dependent quark mass and Li reduction by a heavy quark mass
• Improving spectroscopic lithium abundances. Fitting functions for 3D non-LTE corrections in FGK stars of different metallicity
• Chemical separation of primordial Li${}^{+}$ during structure formation caused by nanogauss magnetic field
• The ${}^6$Li/${}^7$Li isotopic ratio in the metal-poor binary CS22876--032
• Inferring the velocity of early massive stars from the abundances of extremely metal-poor stars
• Line-of-sight velocity and metallicity measurements of the Palomar 5 tidal stream
• The metal-poor end of the Spite plateau. II. Detailed chemical investigation
• A Critique of the Spite Plateau, and the Astration of Primordial Lithium
• On the relative velocity distribution for general statistics and an application to big-bang nucleosynthesis under Tsallis statistics
• Detailed abundances in a sample of very metal poor stars
• Chemical abundance analysis of extremely metal-poor stars in the Sextans dwarf spheroidal galaxy
• Resonant annihilation of long-lived massive colored particles through hadronic collisions
• High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE: II. Binary Fraction
• Galactic Fly-Bys: New Source of Lithium Production
• The Chemical composition of the post-AGB F-supergiant CRL 2688
• Protostellar accretion in low mass metal poor stars and the cosmological lithium problem
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. III. Detection of lithium in the metal-poor bulge dwarf MOA-2010-BLG-285S
• Li distribution, kinematics and detailed abundance analysis among very metal-poor stars in the Galactic halo from the HESP-GOMPA survey
• 7Be charge exchange between 7Be3+ ion and exotic long-lived negatively charged massive particle in big bang nucleosynthesis
• A Solution to Lithium Problem by Long-Lived Stau
• CD -24_17504 revisited: a new comprehensive element abundance analysis
• The long-lived stau as a thermal relic
• Cosmic Rays during BBN as Origin of Lithium Problem
• Initial Li Abundances in the Protogalaxy and Globular Clusters Based upon the Chemical Separation and Hierarchical Structure Formation
• An Enhanced Cosmological Li6 Abundance as a Potential Signature of Residual Dark Matter Annihilations
• Cosmological Lithium Problems
• Primordial Nucleosynthesis After WMAP
• The true nature of HE0057-5959, the most metal-poor Li-rich star
• Extremely Metal-Poor Star Candidates in the SDSS
• Li isotopes in metal-poor halo dwarfs, a more and more complicated story
• The Cosmological Lithium Problem Revisited
• Big Bang Nucleosynthesis with long-lived strongly interacting relic particles
• Observational signatures for depletion in the Spite plateau: solving the cosmological Li discrepancy?
• Primordial helium-3 redux: The helium isotope ratio of the Orion nebula
• Primordial Nucleosynthesis: A Cosmological Probe