Near-Infrared Spectroscopy of Carbon-Enhanced Metal-Poor Stars. I. A SOAR/OSIRIS Pilot Study

Abstract

We report on an abundance analysis for a pilot study of seven Carbon-Enhanced Metal-Poor (CEMP) stars, based on medium-resolution optical and near-infrared spectroscopy. The optical spectra are used to estimate [Fe/H], [C/Fe], [N/Fe], and [Ba/Fe] for our program stars. The near-infrared spectra, obtained during a limited early science run with the new SOAR 4.1m telescope and the Ohio State Infrared Imager and Spectrograph (OSIRIS), are used to obtain estimates of [O/Fe] and 12C/13C. The chemical abundances of CEMP stars are of importance for understanding the origin of CNO in the early Galaxy, as well as for placing constraints on the operation of the astrophysical s-process in very low-metallicity Asymptotic Giant Branch (AGB) stars. This pilot study includes a few stars with previously measured [Fe/H], [C/Fe], [N/Fe],[O/Fe], 12C/13C, and [Ba/Fe], based on high-resolution optical spectra obtained with large-aperture telescopes. Our analysis demonstrates that we are able to achieve reasonably accurate determinations of these quantities for CEMP stars from moderate-resolution optical and near-infrared spectra. This opens the pathway for the study of significantly larger samples of CEMP stars in the near future. Furthermore, the ability to measure [Ba/Fe] for (at least the cooler) CEMP stars should enable one to separate stars that are likely to be associated with s-process enhancements (the CEMP-s stars) from those that do not exhibit neutron-capture enhancements (the CEMP-no stars).

27 pages, including 5 tables, 6 figures, accepted for publication in The Astronomical Journal

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Cited by in corpus (12)

• The Dawes Review 2: Nucleosynthesis and stellar yields of low and intermediate-mass single 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
• Elemental abundances and classification of CEMP stars
• Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. I. Detailed analysis of 15 binary stars with known orbital periods
• Learning about the intermediate neutron-capture process from lead abundances
• Convective H-He Interactions in Massive Population III Stellar Evolution Models
• Pre-supernova mixing in CEMP-no source stars
• Gaia-Sausage-Enceladus star formation history as revealed by detailed elemental abundances
• Constraining Nucleosynthesis in Two CEMP Progenitors Using Fluorine
• Optical and NIR spectroscopy of cool CEMP stars to probe the nucleosynthesis in low mass AGB binary system
• Fluorine abundances in CEMP stars at the lowest metallicity: Hints on the nature of the first stars