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arXiv · 1101.2260

[O/Fe] Estimates for Carbon-Enhanced Metal-Poor Stars from Near-IR Spectroscopy

Catherine R. Kennedy·Thirupathi Sivarani·Timothy C. Beers·Young Sun Lee·Vinicius M. Placco·Silvia Rossi·Norbert Christlieb·Falk Herwig·Bertrand Plez
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Abstract

We report on oxygen abundances determined from medium-resolution near-IR 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 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 asymptotic giant-branch companion.

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Catherine R. Kennedy, Thirupathi Sivarani, Timothy C. Beers, Young Sun Lee, Vinicius M. Placco, Silvia Rossi, Norbert Christlieb, Falk Herwig, Bertrand Plez. 2011-01-12. [O/Fe] Estimates for Carbon-Enhanced Metal-Poor Stars from Near-IR Spectroscopy. https://doi.org/10.1088/0004-6256%2F141%2F3%2F102

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