Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS and GMOS

Abstract

Carbon-enhanced metal-poor (CEMP) stars represent a sizeable fraction of all known metal-poor stars in the Galaxy. Their formation and composition remains a significant topic of investigation within the stellar astrophysics community. We analysed a sample of low-resolution spectra of 30 dwarf stars, obtained using the the visual and near UV FOcal Reducer and low dispersion Spectrograph for the Very Large Telescope (FORS/VLT) of the European Southern Observatory (ESO) and the Gemini Multi-Object Spectrographs (GMOS) at the GEMINI telescope, to derive their metallicity and carbon abundance. We derived C and Ca from all spectra, and Fe and Ba from the majority of the stars. We have extended the population statistics of CEMP stars and have confirmed that in general, stars with a high C abundance belonging to the high C band show a high Ba-content (CEMP-s or -r/s), while stars with a normal C-abundance or that are C-rich, but belong to the low C band, are normal in Ba (CEMP-no).

arXiv commentA&A in press

References in corpus (55)

• The Sloan Digital Sky Survey: Technical Summary
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• SEGUE: A Spectroscopic Survey of 240,000 stars with g=14-20
• First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
• The X-ray counterpart to the gravitational wave event GW 170817
• Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere
• Nucleosynthetic signatures of the first stars
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• A single low-energy, iron-poor supernova as the source of metals in the star SMSS J 031300.36-670839.3
• The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] < -3.5
• The Binary Frequency Among Carbon-Enhanced, s-Process Rich, Metal-Poor Stars
• HE 0557-4840 - Ultra-Metal-Poor and Carbon-Rich
• First stars XII. Abundances in extremely metal-poor turnoff stars,and comparison with the giants
• HE0107-5240, A Chemically Ancient Star.I. A Detailed Abundance Analysis
• HE1327-2326, an unevolved star with [Fe/H]<-5.0. I. A Comprehensive Abundance Analysis
• Normal and Outlying Populations of the Milky Way Stellar Halo at [Fe/H] < -2
• A Subaru/HDS study of Lead (Pb) abundances in eight s-process-element-rich, metal-poor stars
• The intermediate neutron-capture process and carbon-enhanced metal-poor stars
• Observational Constraints on First-Star Nucleosynthesis. I. Evidence for Multiple Progenitors of CEMP-no Stars
• TOPoS: II. On the bimodality of carbon abundance in CEMP stars. Implications on the early chemical evolution of galaxies
• Binarity in Carbon-Enhanced Metal-Poor stars
• First Stars II. Elemental abundances in the extremely metal-poor star CS 22949--037: A diagnostic of early massive supernovae
• The role of binaries in the enrichment of the early Galactic halo. III. Carbon-enhanced metal-poor stars -- CEMP-s stars
• The Hamburg/ESO R-process Enhanced Star survey (HERES) III. HE 0338-3945 and the formation of the r+s stars
• Carbon-enhanced metal-poor stars: the most pristine objects?
• An Elemental Assay of Very, Extremely, and Ultra Metal-Poor Stars
• Carbon-Enhanced Metal-Poor Stars. III. Main-Sequence Turn-Off Stars from the SDSS/SEGUE Sample
• Stellar Archaeology: a Keck Pilot Program on Extremely Metal- Poor Stars From the Hamburg/ESO Survey. III. The Lead (Pb) Star HE 0024-2523
• Abundance Analysis of HE2148-1247, A Star With Extremely Enhanced Neutron Capture Elements
• A primordial star in the heart of the Lion
• First stars IV.CS 29497-030: Evidence for operation of the s-process at very low metallicity
• First stars X. The nature of three unevolved Carbon-Enhanced Metal-Poor stars
• CS22964-161: A Double-Lined Carbon- and s-Process-Enhanced Metal-Poor Binary Star
• New analysis of the two carbon-rich stars CS 22948-27 and CS 29497-34 : binarity and neutron-capture elements
• Three carbon-enhanced metal-poor dwarf stars from the SDSS - Chemical abundances from CO^5BOLD 3D hydrodynamical model atmospheres
• Near-UV Observations of CS29497-030: New Constraints on Neutron-Capture Nucleosynthesis Processes
• The forbidden 1082 nm line of sulphur: the photospheric abundance of sulphur in the Sun and 3D effects
• Neutron-Capture Nucleosynthesis in the First Stars
• SD 1313-0019 -- Another second-generation star with [Fe/H] = -5.0, observed with the Magellan Telescope
• Spectroscopic analysis of metal-poor stars from LAMOST: early results
• Carbon-Enhanced Metal-Poor Stars: CEMP-s and CEMP-no Sub-Classes in the Halo System of the Milky Way
• TOPoS: IV. Chemical abundances from high-resolution observations of seven EMP stars
• Lithium abundances in CEMP stars
• MyGIsFOS: an automated code for parameter determination and detailed abundance analysis in cool stars
• TOPoS: I. Survey design and analysis of the first sample
• The Binary Nature of the Subgiant CH Stars
• X-Shooter GTO: evidence for a population of extremely metal-poor, alpha-poor stars
• TOPoS: III. An ultra iron-poor multiple CEMP system
• An equatorial ultra iron-poor star identified in BOSS
• An in-depth spectroscopic examination of molecular bands from 3D hydrodynamical model atmospheres I. Formation of the G-band in metal-poor dwarf stars
• Chemical analysis of CH stars - I: atmospheric parameters and elemental abundances
• Chemical analysis of CH stars - II: atmospheric parameters and elemental abundances
• High-resolution abundance analysis of HD 140283
• An in-depth spectroscopic examination of molecular bands from 3D hydrodynamical model atmospheres. II. Carbon-enhanced metal-poor 3D model atmospheres

Cited by in corpus (10)

• Abundances and kinematics of carbon-enhanced metal-poor stars in the Galactic halo*; A new classification scheme based on Sr and Ba
• Probing the existence of very massive first stars
• The Most Metal-Poor Stars. V. The CEMP-no Stars in 3D and Non-LTE
• A CEMP-no star in the ultra-faint dwarf galaxy Pisces II
• Metal-poor stars observed with the automated planet finder telescope. I. Discovery of five carbon-enhanced metal-poor stars from LAMOST
• Metal-poor Stars Observed with the Automated Planet Finder Telescope. II. Chemodynamical Analysis of Six Low-Metallicity Stars in the Halo System of the Milky Way
• High-speed stars. II. An unbound star, young stars, bulge metal-poor stars, and Aurora candidates
• TOPoS V: Abundance ratios in a sample of very metal-poor turn-off stars
• A wide angle view of the Sagittarius dwarf spheroidal galaxy -- II. A CEMP-r/s star in the Sagittarius dwarf Spheroidal Galaxy
• Fuzzy Cluster Analysis: Application to Determining Metallicities for Very Metal-poor Stars