Chemical Evolution of R-process Elements in Stars (CERES). I. Stellar parameters and chemical abundances from Na to Zr

Abstract

Aims. The Chemical Evolution of R-process Elements in Stars (CERES) project aims to provide a homogeneous analysis of a sample of metal-poor stars ([Fe/H]<-1.5). We present the stellar parameters and the chemical abundances of elements up to Zr for a sample of 52 giant stars.Methods. We relied on a sample of high signal-to-noise UVES spectra. We determined stellar parameters from Gaia photometry and parallaxes. Chemical abundances were derived using spectrum synthesis and model atmospheres.Results. We determined chemical abundances of 26 species of 18 elements: Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, and Zr. For several stars, we were able to measure both neutral and ionised species, including Si, Sc, Mn, and Zr. We have roughly doubled the number of measurements of Cu for stars at [Fe/H] <= -2.5. The homogeneity of the sample made it possible to highlight the presence of two Zn-rich stars ([Zn/Fe]~+0.7), one r-rich and the other r-poor. We report the existence of two branches in the [Zn/Fe] versus [Ni/Fe] plane and suggest that the high [Zn/Fe] branch is the result of hypernova nucleosynthesis. We discovered two stars with peculiar light neutron-capture abundance patterns: CES1237+1922 (also known as BS 16085-0050), which is ~1 dex underabundant in Sr, Y, and Zr with respect to the other stars in the sample, and CES2250-4057 (also known as HE 2247-4113), which shows a ~1 dex overabundance of Sr with respect to Y and Zr.Conclusions. The high quality of our dataset allowed us to measure hardly detectable ions. This can provide guidance in the development of line formation computations that take deviations from local thermodynamic equilibrium and hydrodynamical effects into account.

References in corpus (93)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Gaia mission
• Discovery of the peculiar supernova 1998bw in the error box of GRB980425
• First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
• Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere
• Nucleosynthesis and Evolution of Massive Metal-Free Stars
• A `Hypernova' model for SN 1998bw associated with gamma-ray burst of 25 April 1998
• Neutrino-induced nucleosynthesis of A>64 nuclei: The nu p-process
• On the astrophysical robustness of neutron star merger r-process
• Neutron-Capture Elements in the Early Galaxy: Insights from a Large Sample of Metal-Poor Giants
• Nucleosynthesis of Zinc and Iron-Peak Elements in Pop III Type II Supernovae : Comparison with abundances of Very Metal-Poor Halo Stars
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• The Hamburg/ESO R-process Enhanced Star survey (HERES) II. Spectroscopic analysis of the survey sample
• A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
• The extreme r-element rich, iron-poor halo giant CS31082-001: Implications for the r-process site(s) and radioactive cosmochronology
• The Stellar Abundances for Galactic Archeology (SAGA) Database - Compilation of the Characteristics of Known Extremely Metal-Poor Stars
• Non-LTE calculations for neutral Na in late-type stars using improved atomic data
• Measurement of stellar age from uranium decay
• The GALAH Survey: Second Data Release
• Spectroscopic Studies of Extremly Metal-Poor Stars with Subaru/HDS:II.The r-process Elements, Including Thorium
• Detailed Abundances for 28 Metal-poor Stars: Stellar Relics in the Milky Way
• Chemical evolution with rotating massive star yields: I. The solar neighbourhood and the s-process elements
• The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] < -3.5
• First Stars VIII -- Enrichment of the neutron-capture elements in the early Galaxy
• Where, oh where has the r-process gone?
• An Analysis of the Shapes of Interstellar Extinction Curves. VII. Milky Way Spectrophotometric Optical-through-Ultraviolet Extinction and Its R-Dependence
• The elemental composition of the Sun II. The iron group elements Sc to Ni
• The first chemical enrichment in the universe and the formation of hyper metal-poor stars
• Abundances of 30 elements in 23 metal-poor stars
• Nucleosynthesis in Early Supernova Winds II: The Role of Neutrinos
• Extremely Metal-Poor Stars. VIII. High-Resolution, High-Signal-To-Noise Analysis of Five Stars with [Fe/H] < -3.5
• First stars XII. Abundances in extremely metal-poor turnoff stars,and comparison with the giants
• NLTE abundances of Mn in a sample of metal-poor stars
• The GALAH Survey: Observational Overview and Gaia DR1 companion
• The intermediate neutron-capture process and carbon-enhanced metal-poor stars
• Bright Metal-Poor Stars from the Hamburg/ESO Survey. I. Selection and Follow-up Observations from 329 Fields
• Non-LTE line formation of Fe in late-type stars - III. 3D non-LTE analysis of metal-poor stars
• The rp-Process in Neutrino-driven Winds
• Chromium: NLTE abundances in metal-poor stars and nucleosynthesis in the Galaxy
• Atomic data for the Gaia-ESO Survey
• From Nuclei to the Cosmos: Tracing Heavy-Element Production with the Oldest Stars
• Production of the entire range of r-process nuclides by black hole accretion disc outflows from neutron star mergers
• Explorations of the r-Processes: Comparisons between Calculations and Observations of Low-Metallicity Stars
• Chemical abundances of the Milky Way thick disk and stellar halo II.: sodium, iron-peak and neutron-capture elements
• Improved Laboratory Transition Probabilities for Neutral Chromium and Re-determination of the Chromium Abundance for the Sun and Three Stars
• Systematic non-LTE study of the $-2.6\le$ [Fe/H] $\le 0.2$ F and G dwarfs in the solar neighbourhood. II. Abundance patterns from Li to Eu
• The $R$-Process Alliance: First Release from the Southern Search for $r$-Process-Enhanced Stars in the Galactic Halo
• Silver and palladium help unveil the nature of a second r-process
• The Hamburg/ESO R-process Enhanced Star survey (HERES). I. Project description, and discovery of two stars with strong enhancements of neutron-capture elements
• The R-Process Alliance: First Release from the Northern Search for r-Process Enhanced Metal-Poor Stars in the Galactic Halo
• Observational constraints on the origin of the elements. I. 3D NLTE formation of Mn lines in late-type stars
• NLTE determination of the sodium abundance in a homogeneous sample of extremely metal-poor stars
• NLTE determination of the aluminium abundance in a homogeneous sample of extremely metal-poor stars
• The Chemical Composition of Carbon-Rich, Very Metal-Poor Stars: A New Class of Mildly Carbon-Rich Objects Without Excess of Neutron-Capture Elements
• Non-LTE Line-Formation and Abundances of Sulfur and Zinc in F, G, and K Stars
• Chemical Abundances of the Milky Way Thick Disk and Stellar Halo I.: Implications of [alpha/Fe] for Star Formation Histories in Their Progenitors
• Iron-Group Abundances in the Metal-Poor Main Sequence Turnoff Star HD~84937
• The GALAH Survey: Non-LTE departure coefficients for large spectroscopic surveys
• Abundances of Sr, Y, and Zr in Metal-Poor Stars and Implications for Chemical Evolution in the Early Galaxy
• Measuring helium abundance difference in giants of NGC 2808
• Non standard s-process in massive rotating stars. Yields of $10-150$ $M_{\odot }$ models at $Z=10^{-3}$
• How many nucleosynthesis processes exist at low metallicity?
• The i-process yields of rapidly-accreting white dwarfs from multicycle He-shell flash stellar evolution models with mixing parameterizations from 3D hydrodynamics simulations
• Asymptotic Giant Branch models at very low metallicity
• The Hamburg/ESO R-process Enhanced Star survey (HERES) X. HE 2252-4225, one more r-process enhanced and actinide-boost halo star
• High-resolution abundance analysis of very metal-poor r-I stars
• The formation of the Milky Way halo and its dwarf satellites, a NLTE-1D abundance analysis. I. Homogeneous set of atmospheric parameters
• The formation of the Milky Way halo and its dwarf satellites; a NLTE-1D abundance analysis. II. Early chemical enrichment
• Nine New Metal-Poor Stars on the Subgiant and Red Horizontal Branches with High Levels of r-process Enhancement
• MyGIsFOS: an automated code for parameter determination and detailed abundance analysis in cool stars
• NLTE study of scandium in the Sun
• i-Process Contribution of Rapidly Accreting White Dwarfs to the Solar Composition of First-Peak Neutron-Capture Elements
• Observational constraints on the origin of the elements. III. Evidence for the dominant role of sub-Chandrasekhar SN Ia in the chemical evolution of Mn and Fe in the Galaxy
• Facing the problems on the determination of stellar temperatures and gravities: Galactic globular clusters
• Evidence for $\gtrsim 4$ Gyr timescales of neutron star mergers from Galactic archaeology
• Zinc in the Sculptor dwarf spheroidal galaxy
• Abundance patterns of the light neutron-capture elements in very and extremely metal-poor stars
• Galactic evolution of Copper in the light of NLTE computations
• Stellar abundances and presolar grains trace the nucleosynthetic origin of molybdenum and ruthenium
• Influence of departures from LTE on calcium, titanium, and iron abundance determinations in cool giants of different metallicities
• A New Test of Copper and Zinc Abundances in Late-Type Stars Using Ultraviolet Cu II and Zn II Lines
• Formation of Zr I and II lines under non-LTE conditions of stellar atmospheres
• Constraining nucleosynthesis in neutrino-driven winds: observations, simulations and nuclear physics
• Using the CIFIST grid of CO5BOLD 3D model atmospheres to study the effects of stellar granulation on photometric colours. I. Grids of 3D corrections in the UBVRI, 2MASS, Hipparcos, Gaia, and SDSS systems
• Neutron-capture elements in dwarf galaxies II: Challenges for the s- and i-processes at low metallicity
• Unusual neutron-capture nucleosynthesis in a carbon-rich Galactic bulge star
• Mono-enriched stars and Galactic chemical evolution -- Possible biases in observations and theory
• NLTE analysis of copper lines in different stellar populations
• Chemical Compositions of Four Metal-poor Giants
• Influence of Inelastic Collisions with Hydrogen Atoms on the Formation of Al I and Si I Lines in Stellar Spectra
• Evolution of O Abundance Relative to Fe
• The solar photospheric abundance of zirconium
• Hypernova Nucleosynthesis and Galactic Chemical Evolution

Cited by in corpus (11)

• Tracing Pop III supernovae with extreme energies through the Sculptor dwarf spheroidal galaxy
• MINCE I. Presentation of the project and of the first year sample
• Chemical Evolution of R-process Elements in Stars (CERES): IV. An observational run-up of the third r-process peak with Hf, Os, Ir, and Pt
• Revisiting inelastic Cu+H collisions and the non-LTE Galactic evolution of copper
• Chemodynamical study of two CEMP-no stars from the Hamburg/ESO Survey
• Untangling the Sources of Abundance Dispersion in Low-Metallicity Stars
• Chemical Evolution of R-process Elements in Stars (CERES). III. Chemical abundances of neutron capture elements from Ba to Eu
• Unlocking the mystery of Sr synthesis in the early Galaxy through analysis of barium isotopes in very metal-poor stars
• Neutron-Capture Element Signatures in Globular Clusters: Insights from the Gaia-ESO Survey
• The true nature of HE0057-5959, the most metal-poor Li-rich star
• MINCE III. Detailed chemical analysis of the UVES sample