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High-Resolution Spe...
High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the Skymapper Survey
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Jacobson, Heather R. (författare)
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Keller, Stefan (författare)
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Frebel, Anna (författare)
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Casey, Andrew R. (författare)
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Asplund, Martin (författare)
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Bessell, Michael S. (författare)
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Da Costa, Gary S. (författare)
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- Lind, Karin (författare)
- Uppsala universitet,Observationell astrofysik
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Marino, Anna F. (författare)
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Norris, John E. (författare)
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Pena, Jose M. (författare)
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Schmidt, Brian P. (författare)
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Tisserand, Patrick (författare)
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Walsh, Jennifer M. (författare)
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Yong, David (författare)
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Yu, Qinsi (författare)
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(creator_code:org_t)
- 2015
- 2015
- Engelska.
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 807:2
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- 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 angstrom 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 [Fe/H] <= -3.0. Nine have [Fe/H] <= -3.5, with three at [Fe/H] similar to -4. 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: >2. Only one other star is known to have a comparable value. Seven stars are "CEMP-no" stars ([C/Fe] > 0.7, [Ba/Fe] < 0). 21 stars exhibit mild r-process element enhancements (0.3 <= [Eu/Fe] < 1.0), while four stars have [Eu/Fe] >= 1.0. 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.
Ämnesord
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- stars: abundances
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Jacobson, Heathe ...
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Keller, Stefan
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Frebel, Anna
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Casey, Andrew R.
-
Asplund, Martin
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Bessell, Michael ...
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visa fler...
-
Da Costa, Gary S ...
-
Lind, Karin
-
Marino, Anna F.
-
Norris, John E.
-
Pena, Jose M.
-
Schmidt, Brian P ...
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Tisserand, Patri ...
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Walsh, Jennifer ...
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Yong, David
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Yu, Qinsi
-
visa färre...
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Uppsala universitet