Artículos de revistas
[O/Fe] ESTIMATES FOR CARBON-ENHANCED METAL-POOR STARS FROM NEAR-INFRARED SPECTROSCOPY
Fecha
2011Registro en:
ASTRONOMICAL JOURNAL, v.141, n.3, 2011
0004-6256
10.1088/0004-6256/141/3/102
Autor
KENNEDY, Catherine R.
SIVARANI, Thirupathi
BEERS, Timothy C.
LEE, Young Sun
PLACCO, Vinicius M.
ROSSI, Silvia
CHRISTLIEB, Norbert
HERWIG, Falk
PLEZ, Bertrand
Institución
Resumen
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.