NOAO > Observing Info > Approved Programs > 2011A-0205
|
NOAO > Observing Info > Approved Programs > 2011A-0205 |
|
PI: Timothy Beers, Michigan State University, beers@pa.msu.edu
Address: Department of Physics and Astronomy, East Lansing, MI, 48824-1116, USA
CoI: Vinicius Placco, Universidade de Sao Paulo
CoI: Catherine Kennedy, Michigan State University
CoI: Silvia Rossi, Universidade de Sao Paulo
CoI: Norbert Christlieb, University of Heidelberg
CoI: Young Sun Lee, Michigan State University
CoI: Thirupathi Sivarani, Indian Institute of Astrophysics
Title: A Survey for Unrecognized Carbon-Enhanced Metal-Poor Stars in the Galaxy
Abstract:
Carbon-Enhanced Metal-Poor (CEMP) stars are of great astrophysical interest
for a host of reasons. Although the majority (80%) of such stars are known to
be associated with mass-transfer events from a companion star that has
evolved to the AGB stage (the CEMP-s stars), 20% of these stars do not
exhibit enhanced s-process elements (the CEMP-no stars), and hence may be
associated with a variety of other carbon-production mechanisms in the early
Universe. A list of previously unidentified candidate CEMP stars from the
Hamburg/ESO prism survey has been compiled, based on the strength of a new
extended CH G-band index. Follow-up spectroscopy for a pilot sample of 132
candidates was obtained with SOAR; results show that the majority of
candidates possess prominent carbon absorption features at 4300A. We propose
to acquire additional spectroscopic data for this metallicity unbiased
sample, using GMOS-S observations. This will enable the identification of new
CEMP stars over a wide range of [Fe/H], that includes representatives of the
inner- and outer-halo populations, as well as the metal-weak thick disk and
thick disk. Metallicities and carbon abundances for such stars work as probes
of stellar population distributions in the Galaxy and its nearby satellites.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
|
NOAO > Observing Info > Approved Programs > 2011A-0205 |
|