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Carbon-Enhanced Metal-Poor (CEMP) stars

Published online by Cambridge University Press:  09 March 2010

Wako Aoki*
Affiliation:
National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan email: aoki.wako@nao.ac.jp
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Abstract

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A significant fraction of metal-poor stars have large over-abundances of carbon, and are called Carbon-Enhanced Metal-Poor (CEMP) stars. Most of CEMP stars also show excesses of heavy neutron-capture elements like Ba, indicating that their origin is the nucleosynthesis in AGB stars. Remaining CEMP stars that have Ba abundances as low as non-carbon-rich stars appear in the lowest metallicity range ([Fe/H]≲−2.5), and connections with the two most iron-deficient stars (so-called Hyper Metal-Poor stars) are suggested. Although the origins of the carbon-excesses in these objects have not been well identified, some objects suggest contributions of faint supernovae. Remaining problems on CEMP stars, such as the binary fraction, excess of r-process elements, are discussed.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2010

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