TY - JOUR
T1 - HIGH-RESOLUTION SPECTROSCOPIC STUDY of EXTREMELY METAL-POOR STAR CANDIDATES from the SKYMAPPER SURVEY
AU - Jacobson, Heather R.
AU - Keller, Stefan
AU - Frebel, Anna
AU - Casey, Andrew R.
AU - Asplund, Martin
AU - Bessell, Michael S.
AU - Costa, Gary S.Da
AU - Lind, Karin
AU - Marino, Anna F.
AU - Norris, John E.
AU - Peña, José M.
AU - Schmidt, Brian P.
AU - Tisserand, Patrick
AU - Walsh, Jennifer M.
AU - Yong, David
AU - Yu, Qinsi
N1 - Publisher Copyright:
© 2015. The American Astronomical Society. All rights reserved.
PY - 2015/7/10
Y1 - 2015/7/10
N2 - The SkyMapper Southern Sky Survey is carrying out a search for the most metal-poor stars in the Galaxy. It identifies candidates by way of its unique filter set which allows for estimation of stellar atmospheric parameters. The set includes a narrow filter centered on the Ca ii K 3933 line, enabling a robust estimate of stellar metallicity. Promising candidates are then confirmed with spectroscopy. We present the analysis of Magellan Inamori Kyocera Echelle high-resolution spectroscopy of 122 metal-poor stars found by SkyMapper in the first two years of commissioning observations. Forty-one stars have . Nine have , with three at . A 1D LTE abundance analysis of the elements Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, Ba, and Eu shows these stars have [X/Fe] ratios typical of other halo stars. One star with low [X/Fe] values appears to be "Fe-enhanced," while another star has an extremely large [Sr/Ba] ratio: Only one other star is known to have a comparable value. Seven stars are "CEMP-no" stars (, ). 21 stars exhibit mild r-process element enhancements (), while four stars have . These results demonstrate the ability to identify extremely metal-poor stars from SkyMapper photometry, pointing to increased sample sizes and a better characterization of the metal-poor tail of the halo metallicity distribution function in the future.
AB - The SkyMapper Southern Sky Survey is carrying out a search for the most metal-poor stars in the Galaxy. It identifies candidates by way of its unique filter set which allows for estimation of stellar atmospheric parameters. The set includes a narrow filter centered on the Ca ii K 3933 line, enabling a robust estimate of stellar metallicity. Promising candidates are then confirmed with spectroscopy. We present the analysis of Magellan Inamori Kyocera Echelle high-resolution spectroscopy of 122 metal-poor stars found by SkyMapper in the first two years of commissioning observations. Forty-one stars have . Nine have , with three at . A 1D LTE abundance analysis of the elements Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, Ba, and Eu shows these stars have [X/Fe] ratios typical of other halo stars. One star with low [X/Fe] values appears to be "Fe-enhanced," while another star has an extremely large [Sr/Ba] ratio: Only one other star is known to have a comparable value. Seven stars are "CEMP-no" stars (, ). 21 stars exhibit mild r-process element enhancements (), while four stars have . These results demonstrate the ability to identify extremely metal-poor stars from SkyMapper photometry, pointing to increased sample sizes and a better characterization of the metal-poor tail of the halo metallicity distribution function in the future.
KW - abundances
KW - stars
UR - http://www.scopus.com/inward/record.url?scp=84937010962&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/807/2/171
DO - 10.1088/0004-637X/807/2/171
M3 - Article
SN - 0004-637X
VL - 807
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 171
ER -