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A Search for Unrecognized Carbon-Enhanced Metal-Poor Stars

Published online by Cambridge University Press:  09 March 2010

Vinicius M. Placco ,
Catherine R. Kennedy ,
Silvia Rossi ,
Timothy C. Beers ,
Norbert Christlieb  and
Thirupathi Sivarani
Vinicius M. Placco
Affiliation:
Departamento de Astronomia - Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, SP 05508-900, Brazil email: vmplacco@astro.iag.usp.br
Catherine R. Kennedy
Affiliation:
Department of Physics & Astronomy and JINA: Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824, USA
Silvia Rossi
Affiliation:
Departamento de Astronomia - Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, SP 05508-900, Brazil email: vmplacco@astro.iag.usp.br
Timothy C. Beers
Affiliation:
Department of Physics & Astronomy and JINA: Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824, USA
Norbert Christlieb
Affiliation:
Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Königstuhl 12, 69117, Heidelberg, Germany
Thirupathi Sivarani
Affiliation:
Indian Institute of Astrophysics, 2nd block, Koramangala, Bangalore 560034, India
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Abstract

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We have developed a new procedure to search for Carbon-Enhanced Metal-Poor (CEMP) stars from the Hamburg/ESO (HES) prism-survey plates. This method uses an extended line index for the CH G-band, which we demonstrate to have superior behavior when compared to the narrower G-band index formerly employed for these spectra.

A first subsample, biased towards brighter stars (B<15.5), has been extracted from the scanned HES plates. After visual inspection (to eliminate spectra compromised by plate defects, overlapping spectra, etc., and to carry out rough spectral classifications), a list of 669 previously unidentified candidate CEMP stars was compiled. Follow-up spectroscopy for a pilot sample of 132 candidates was obtained on the SOAR 4.1m telescope. Our results show that most of the stars observed lie in the targetted metallicity range, and possess prominent carbon absorption features at 4300Å. The success rate for the identification of new CEMP stars is ~50% for [Fe/H]< −2.0. For stars with [Fe/H]< −2.5, the ratio increases to 100%.

Keywords

stars: abundancesstars: carbonstars: Population IIGalaxy: halosurveys
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S265: Chemical Abundances in the Universe: Connecting First Stars to Planets , August 2009 , pp. 132 - 133
Copyright
Copyright © International Astronomical Union 2010

References

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