Journal Articles The Astronomical Journal Year : 2011

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

Catherine R. Kennedy
  • Function : Author
Thirupathi Sivarani
  • Function : Author
Timothy C. Beers
  • Function : Author
Young Sun Lee
  • Function : Author
Vinicius M. Placco
  • Function : Author
Silvia Rossi
  • Function : Author
  • PersonId : 1043775
Norbert Christlieb
  • Function : Author
Falk Herwig
  • Function : Author
Bertrand Plez

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.

Dates and versions

hal-00651242 , version 1 (13-12-2011)

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Catherine R. Kennedy, Thirupathi Sivarani, Timothy C. Beers, Young Sun Lee, Vinicius M. Placco, et al.. [O/Fe] Estimates for Carbon-Enhanced Metal-Poor Stars from Near-IR Spectroscopy. The Astronomical Journal, 2011, 141 (3), pp.102. ⟨10.1088/0004-6256/141/3/102⟩. ⟨hal-00651242⟩
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