First stars XII. Abundances in extremely metal-poor turnoff stars,and comparison with the giants

  title={First stars XII. Abundances in extremely metal-poor turnoff stars,and comparison with the giants},
  author={Piercarlo Bonifacio and Monique Spite and Roger. Cayrel and Vanessa Hill and Franccois Spite and P. François and Bertrand Plez and Hans-G. Ludwig and Elisabetta Caffau and Paolo Molaro and {\'E}ric Depagne and Johannes Andersen and Beatriz Barbuy and Timothy C. Beers and Birgitta Nordstrom and F. Primas Cifist Gepi and Observatoire de Paris INAF- OA Trieste Cassiopee and Observatoire de la Cote d'Azur Graal and Universite de Montpellier Department of PhysicsAstronomy and Uppsala Astronomical Observatory Las Cumbres Observatory T Iag and Universidade de Sao Paulo Department of PhysicsAstronomy and Csce and Jin-a and M. F. Sterzik European Southern Observatory},
  journal={Astronomy and Astrophysics},
Context. The detailed chemical abundances of extremely metal-poor (EMP) stars are key guides to understanding the early chemical evolution of the Galaxy. Most existing data, however, treat giant stars that may have experienced internal mixing later. Aims. We aim to compare the results for giants with new, accurate abundances for all observable elements in 18 EMP turno. stars. Methods. VLT/UVES spectra at R similar to 45 000 and S/N similar to 130 per pixel (lambda lambda 330-1000 nm) are… 

First stars - XIII. Two extremely metal-poor RR Lyrae stars

Context. The chemical composition of extremely metal-poor stars (EMP stars; [Fe/H] < ∼− 3) is a unique tracer of early nucleosynthesis in the Galaxy. As such stars are rare, we wish to find classes

First stars - XIV. Sulfur abundances in extremely metal-poor stars

Context. Precise S abundances are important in the study of the early chemical evolution of the Galaxy. In particular the site of th e formation remains uncertain because, at low metallicity, the

TOPoS. IV. Chemical abundances from high-resolution observations of seven extremely metal-poor stars

Context. Extremely metal-poor (EMP) stars provide us with indirect information on the first generations of massive stars. The TOPoS survey has been designed to increase the census of these stars and

TOPoS V: Abundance ratios in a sample of very metal-poor turn-off stars

Extremely metal-poor stars are keys to understand the early evolution of our Galaxy. The ESO large programme TOPoS has been tailored to analyse a new set of metal-poor turn-off stars, whereas most of

Detailed abundances in a sample of very metal-poor stars

Context. Unevolved metal-poor stars bore witness to the early evolution of the Galaxy, and the determination of their detailed chemical composition is an important tool to understand its chemical

Chemical abundances of distant extremely metal-poor unevolved stars

Context. The old Galactic halo stars hold the fossil record of the inte rstellar medium chemical composition at the time of their formation. Most of the stars studied so far are relatively ne ar to

Extremely metal-poor stars in SDSS fields

Some insight on the first generation of stars can be obtained from the chemical composition of their direct descendants, extremely metal-poor stars (EMP), with metallicity less than or equal to

Mono-enriched stars and Galactic chemical evolution

A long sought after goal using chemical abundance patterns derived from metal-poor stars is to understand the Galactic chemical evolution (GCE) and to pin down the nature of the first stars (Pop


Chemical abundances of 26 metal-poor dwarfs and giants are determined from high-resolution and high signal-to-noise ratio spectra obtained with the Subaru/High Dispersion Spectrograph. The sample is

Explaining the Ba, Y, Sr, and Eu abundance scatter in metal-poor halo stars: constraints to the r-process

Context. Thanks to the heroic observational campaigns carried out in recent years we now have large samples of metal-poor stars for which measurements of detailed abundances exist. [...] These data



First stars XI. Chemical composition of the extremely metal-poor dwarfs in the binary CS 22876-032

Context: Unevolved metal-poor stars constitute a fossil record of the early Galaxy, and can provide invaluable information on the properties of the first generations of stars. Binary systems also

First stars VIII. Enrichment of the neutron-capture elements in the early Galaxy

Context: Extremely metal-poor (EMP) stars in the halo of the Galaxy are sensitive probes of the production of the first heavy elements and the efficiency of mixing in the early interstellar medium.

First Stars. III. A detailed elemental abundance study of four extremely metal-poor giant stars ?;??

This paper reports detailed abundance analyses for four extremely metal-poor (XMP) giant stars with (Fe=H)< 3:8, based on high-resolution, high-S=N spectra from the ESO VLT (Kueyen/UVES) and LTE

First stars VII - Lithium in extremely metal poor dwarfs

Context. The primordial lithium abundance is a key prediction of models of big bang nucleosynthesis, and its abundance in metal-poor dwarfs (the Spite plateau) is an important, independent

First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements

We have investigated the poorly-understood origin of nitrogen in the early Galaxy by determining N abundances from the NH band at 336 nm in 35 extremely metal-poor halo giants, with carbon and oxygen

New Extremely Metal-Poor Stars in the Galactic Halo

We present a detailed abundance analysis based on high-resolution and high signal-to-noise spectra of eight extremely metal-poor (EMP) stars with [ Fe/H ] ≲ − 3.5 dex, four of which are new. Only

Abundances of Extremely Metal-poor Star Candidates

We present chemical abundances for 110 stars identified in objective-prism surveys as candidates for being very metal-poor. The abundances are derived from high-S/N, intermediate-resolution spectra

Atomic Diffusion and Mixing in Old Stars. I. Very Large Telescope FLAMES-UVES Observations of Stars in NGC 6397

We present a homogeneous photometric and spectroscopic analysis of 18 stars along the evolutionary sequence of the metal-poor globular cluster NGC 6397 ([Fe/H] ≈ -2), from the main-sequence turnoff

Detailed Abundances for 28 Metal-poor Stars: Stellar Relics in the Milky Way

We present the results of an abundance analysis for a sample of stars with –4 < [ Fe/H ] < − 2. The data were obtained with the HIRES spectrograph at Keck Observatory. The set includes 28 stars, with

First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy

In the framework of the ESO Large Programme "First Stars", very high-quality spectra of some 70 very metal-poor dwarfs and giants were obtained with the ESO VLT and UVES spectrograph. These stars are