Chemical analysis of CH stars - I: atmospheric parameters and elemental abundances

Abstract

Results from high-resolution spectral analyses of a selected sample of CH stars are presented. Detailed chemical composition studies of these objects, which could reveal abundance patterns that in turn provide information regarding nucleosynthesis and evolutionary status, are scarce in the literature. We conducted detailed chemical composition studies for these objects based on high resolution (R ~ 42000) spectra. The spectra were taken from the ELODIE archive and cover the wavelength range from 3900 to 6800 A, in the wavelength range. We estimated the stellar atmospheric parameters, the effective temperature Teff, the surface gravity log g, and metallicity [Fe/H] from Local thermodynamic equilibrium analyses using model atmospheres. Estimated temperatures of these objects cover a wide range from 4550 K to 6030 K, the surface gravity from 1.8 to 3.8 and metallicity from -0.18 to -1.4. We report updates on elemental abundances for several heavy elements and present estimates of abundance ratios of Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu and Dy with respect to Fe. For the object HD 188650 we present the first abundance analyses results based on a high resolution spectrum. Enhancements of heavy elements relative to Fe, that are characteristic of CH stars are evident from our analyses for most of the objects. A parametric model based study is performed to understand the relative contributions from the s- and r-processes to the abundances of the heavy elements.

arXiv comment18 pages, 14 figures, published in MNRAS

References in corpus (54)

• The chemical composition of the Sun
• Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03
• Local Kinematics and the Local Standard of Rest
• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
• Neutron capture in low mass Asymptotic Giant Branch stars: cross sections and abundance signatures
• Elemental Abundance Survey of The Galactic Thick Disk
• Nucleosynthesis in neutrino-driven winds: I. The physical conditions
• Radial Velocities for 889 Late-type Stars
• SB9: The Ninth Catalogue of Spectroscopic Binary Orbits
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• Abundances and Kinematics of Field Halo and Disk Stars I: Observational Data and Abundance Analysis
• Nucleosynthesis and mixing on the Asymptotic Giant Branch. III. Predicted and observed s-process abundances
• Neutron star mergers versus core-collapse supernovae as dominant r-process sites in the early Galaxy
• The Binary Frequency Among Carbon-Enhanced, s-Process Rich, Metal-Poor Stars
• The ELODIE archive
• The s-Process in Low Metallicity Stars. II. Interpretation of High-Resolution Spectroscopic Observations with AGB models
• $s$-process production in rotating massive stars at solar and low metallicities
• Deep Mixing of He-3: Reconciling Big Bang and Stellar Nucleosynthesis
• A Subaru/HDS study of Lead (Pb) abundances in eight s-process-element-rich, metal-poor stars
• Spectroscopic Studies of Very Metal-Poor Stars with the Subaru High Dispersion Spectrograph. III. Light Neutron-Capture Elements
• Galactic evolution of rapid neutron capture process abundances: the inhomogeneous approach
• On the correlation of elemental abundances with kinematics among galactic disk stars
• Binarity in Carbon-Enhanced Metal-Poor stars
• Vertical distribution of Galactic disk stars IV - AMR and AVR from clump giants
• Galactic r-process enrichment by neutron star mergers in cosmological simulations of a Milky Way-mass galaxy
• Wind Roche-lobe overflow: Application to carbon-enhanced metal-poor stars
• The Hamburg/ESO R-process Enhanced Star survey (HERES) III. HE 0338-3945 and the formation of the r+s stars
• Neutron Capture Elements in s-Process-Rich, Very Metal-Poor Stars
• The stellar content of the Hamburg/ESO survey. II. A large, homogeneously-selected sample of high latitude carbon 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
• Abundance Analysis of HE2148-1247, A Star With Extremely Enhanced Neutron Capture Elements
• s-Process in Low Metallicity Stars. III. Individual analysis of CEMP-s and CEMP-s/r with AGB models
• On the Perils of Hyperfine Splitting: A reanalysis of Mn and Sc Abundance Trends
• A Keck HIRES Doppler Search for Planets Orbiting Metal-Poor Dwarfs. II. On the Frequency of Giant Planets in the Metal-Poor Regime
• Binary properties of CH and Carbon-Enhanced Metal-Poor stars
• New analysis of the two carbon-rich stars CS 22948-27 and CS 29497-34 : binarity and neutron-capture elements
• 3D Numerical Experimentation on the Core Helium Flash of low-mass Red Giants
• The HARPS search for southern extrasolar planets XXV. Results from the metal-poor sample
• A high-resolution spectral analysis of three carbon-enhanced metal-poor stars
• Observational evidence for a different IMF in the early Galaxy
• The Origins of Two Classes of Carbon-Enhanced, Metal-Poor Stars
• Low-mass supernovae in the early Galactic halo: source of the double r/s-process enriched halo stars?
• Analysis of 26 Barium Stars I. Abundances
• Cooler and bigger than thought? Planetary host stellar parameters from the InfraRed Flux Method
• Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. II. Statistical analysis of a sample of 67 CEMP-$s$ stars
• Ba & Eu Abundances in M15 giant stars
• CH stars at High Galactic Latitudes
• The Binary Nature of the Subgiant CH Stars
• Analysis of 26 Barium Stars II. Contributions of s-, r- and p-processes in the production of heavy elements
• The CH fraction of Carbon stars at high Galactic latitudes
• The solar photospheric abundance of europium. Results from CO5BOLD 3-D hydrodynamical model atmospheres
• Subaru/HDS study of CH stars: elemental abundances for stellar neutron-capture process studies
• Polarimetric studies of carbon stars at high Galactic latitude

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• A Comparison of Stellar Elemental Abundance Techniques and Measurements
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• Constraints of the physics of low-mass AGB stars from CH and CEMP stars
• Low-mass low-metallicity AGB stars as an efficient i-process site explaining CEMP-rs stars
• Hubble Space Telescope Near-Ultraviolet Spectroscopy of Bright CEMP-s Stars
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• Spectroscopic study of four metal-poor carbon stars from the Hamburg/ESO Survey: On confirming the low-mass nature of their companions
• Chemical analysis of three barium stars: HD 51959, HD 88035, HD 121447
• Probing the nucleosynthetic contribution of low-metallicity, low-mass star companions of CEMP stars
• High-resolution spectroscopic analysis of four new chemically peculiar stars
• Abundance analysis of s-process enhanced barium stars
• Chemical abundances of three new Ba stars from the Keck/HIRES spectra
• Modeling the progenitors of low-mass post-accretion binaries