[O/Fe] ESTIMATES FOR CARBON-ENHANCED METAL-POOR STARS FROM NEAR-INFRARED SPECTROSCOPY

Journal Article · Tue Mar 15 04:00:00 EDT 2011 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/141/3/102· OSTI ID:21583194

Kennedy, Catherine R; Beers, Timothy C; Lee, Young Sun ^[1]; Sivarani, Thirupathi ^[2]; Placco, Vinicius M; Rossi, Silvia ^[3]; Christlieb, Norbert ^[4]; Herwig, Falk ^[5]; Plez, Bertrand ^[6]

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1. Department of Physics and Astronomy and JINA: Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States)
2. Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore 560034 (India)
3. Departamento de Astronomia-Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Sao Paulo, SP 05508-900 (Brazil)
4. Zentrum fuer Astronomie der Universitaet Heidelberg, Landessternwarte, Koenigstuhl 12, 69117 Heidelberg (Germany)
5. Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P5C2 (Canada)
6. GRAAL-CNRS, Universite Montpellier II-UMR 5024, Place Eugene Bataillon, F-34095, Montpellier Cedex 05 (France)

We report on oxygen abundances determined from medium-resolution near-infrared spectroscopy for a sample of 57 carbon-enhanced metal-poor (CEMP) stars selected from the Hamburg/ESO Survey. The majority of our program stars exhibit oxygen-to-iron ratios in the range +0.5< [O/Fe]<+2.0. The [O/Fe] values for this sample are statistically compared to available high-resolution estimates for known CEMP stars as well as to high-resolution estimates for a set of carbon-normal metal-poor stars. Carbon, nitrogen, and oxygen abundance patterns for a sub-sample of these stars are compared to yield predictions for very metal-poor asymptotic giant branch (AGB) abundances in the recent literature. We find that the majority of our sample exhibit patterns that are consistent with previously studied CEMP stars having s-process-element enhancements and thus have very likely been polluted by carbon- and oxygen-enhanced material transferred from a metal-poor AGB companion.

• OSTI ID: 21583194
• Journal Information: Astronomical Journal (New York, N.Y. Online), Journal Name: Astronomical Journal (New York, N.Y. Online) Journal Issue: 3 Vol. 141; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION SPECTROSCOPY
ABUNDANCE
CARBON
ELEMENT ABUNDANCE
ELEMENTS
EVOLUTION
GALAXIES
INFRARED SPECTRA
IRON
METALS
NITROGEN
NONMETALS
OXYGEN
S PROCESS
SPECTRA
SPECTROSCOPY
STAR EVOLUTION
STARS
TRANSITION ELEMENTS