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

Abstract

We present detailed chemical analyses for a sample of twelve stars selected from the CH star catalogue of Bartkevicius (1996). The sample includes two confirmed binaries, four objects that are known to show radial velocity variations and the rest with no information on the binary status. A primary objective is to examine if all these objects exhibit chemical abundances characteristics of CH stars, based on detailed chemical composition study using high resolution spectra. We have used high resolution (R ~ 42000) spectra from the ELODIE archive. These spectra cover 3900 to 6800 Angstrom in the wavelength range. We have estimated the stellar atmospheric parameters, the effective temperature Teff, the surface gravity log g, and metallicity [Fe/H] from LTE analysis using model atmospheres. Estimated temperatures of these objects cover a wide range from 4200 K to 6640 K, the surface gravity from 0.6 to 4.3 and metallicity from -0.13 to -1.5. We report updates on elemental abundances for several heavy elements, Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu and Dy. For the object HD 89668 we present the first abundance analyses results. Enhancement of heavy elements relative to Fe, a characteristic property of CH stars is evident from our analyses in case of four objects, HD 92545, HD 104979, HD 107574 and HD 204613. A parametric model based study is performed to understand the relative contributions from the s- and r-process to the abundances of the heavy elements.

arXiv comment16 pages, 15 figures, Accepted for publication in MNRAS

References in corpus (40)

• 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
• Neutron capture in low mass Asymptotic Giant Branch stars: cross sections and abundance signatures
• 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
• Pulkovo Compilation of Radial Velocities for 35495 Hipparcos Stars in a Common System
• The ELODIE archive
• Spectroscopic stellar parameters for 582 FGK stars in the HARPS volume-limited sample. Revising the metallicity-planet correlation
• A holistic approach to carbon-enhanced metal-poor stars
• 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
• Two distinct halo populations in the solar neighborhood. II. Evidence from stellar abundances of Mn, Cu, Zn, Y, and Ba
• Vertical distribution of Galactic disk stars IV - AMR and AVR from clump giants
• The atmospheric parameters and spectral interpolator for the stars of MILES
• The RAdial Velocity Experiment (RAVE): Third Data Release
• 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
• Carbon-Enhanced Metal-Poor Stars in the Inner and Outer Halo Components of the Milky Way
• The Chemical Composition of Carbon-Rich, Very Metal-Poor Stars: A New Class of Mildly Carbon-Rich Objects Without Excess of Neutron-Capture Elements
• On the Perils of Hyperfine Splitting: A reanalysis of Mn and Sc Abundance Trends
• Abundances of neutron-capture elements in stars of the galactic disk substructures
• A Keck HIRES Doppler Search for Planets Orbiting Metal-Poor Dwarfs. II. On the Frequency of Giant Planets in the Metal-Poor Regime
• Stellar population models in the UV: I. Characterisation of the New Generation Stellar Library
• New analysis of the two carbon-rich stars CS 22948-27 and CS 29497-34 : binarity and neutron-capture elements
• 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
• Analysis of 26 Barium Stars I. Abundances
• Cooler and bigger than thought? Planetary host stellar parameters from the InfraRed Flux Method
• 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
• Chemical analysis of CH stars - I: atmospheric parameters and elemental abundances
• Polarimetric studies of carbon stars at high Galactic latitude

Cited by in corpus (23)

• Chemical tagging with APOGEE: Discovery of a large population of N-rich stars in the inner Galaxy
• Barium & related stars and their white-dwarf companions I. Giant stars
• The s Process and Beyond
• The detection and characterisation of 54 massive companions with the SOPHIE spectrograph -- 7 new brown dwarfs and constraints on the BD desert
• 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
• Chemodynamics of newly identified giants with globular cluster like abundance patterns in the bulge, disk, and halo of the Milky Way
• Chemical analysis of CH stars - III: Atmospheric parameters and elemental abundances
• Galactic ArchaeoLogIcaL ExcavatiOns (GALILEO) I. An updated census of APOGEE N-rich giants across the Milky Way
• Barium and related stars, and their white-dwarf companions. III. The masses of the white dwarfs
• Subaru/HDS study of CH stars: elemental abundances for stellar neutron-capture process studies
• Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS and GMOS
• Three new barium dwarfs with WD companions: BD+68 1027, RE J0702+129 and BD+80 670
• Chemical analysis of two extremely metal-poor stars HE 2148-2039 and HE 2155-2043
• HCT/HESP study of two carbon stars from the LAMOST survey
• APOGEE-2 Discovery of a Large Population of Relatively High-Metallicity Globular Cluster Debris
• Chemical analysis of three barium stars: HD 51959, HD 88035, HD 121447
• Spectroscopic study of four metal-poor carbon stars from the Hamburg/ESO Survey: On confirming the low-mass nature of their companions
• The s-process enriched star HD 55496: origin from a globular cluster or from the tidal disruption of a dwarf galaxy?
• Probing the nucleosynthetic contribution of low-metallicity, low-mass star companions of CEMP stars
• Abundance analysis of s-process enhanced barium stars
• Modeling the progenitors of low-mass post-accretion binaries
• S-Process Nucleosynthesis in Chemically Peculiar Binaries