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The Gaia-ESO Survey: alpha-abundances of metal-poor stars

Jackson-Jones, R.; Jofre, P.; Hawkins, K.; Hourihane, A.; Gilmore, G.; Kordopatis, G.; Worley, C.; Randich, S.; Vallenari, A. and Bensby, Thomas LU , et al. (2014) In Astronomy & Astrophysics 571.
Abstract
We performed a detailed study of the ratio of low-alpha to high-alpha stars in the Galactic halo as observed by the Gaia-ESO Survey. Using a sample of 381 metal-poor stars from the second internal data release, we found that the value of this ratio did not show evidence of systematic trends as a function of metallicity, surface gravity, Galactic latitude, Galactic longitude, height above the Galactic plane, and Galactocentric radius. We conclude that the alpha(poor)/alpha(rich) value of 0.28 +/- 0.08 suggests that in the inner halo, the larger portion of stars were formed in a high star formation rate environment, and about 15% of the metal-poor stars originated from much lower star formation rate environments.
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publication status
published
subject
keywords
stars: abundances, Galaxy: halo
in
Astronomy & Astrophysics
volume
571
publisher
EDP Sciences
external identifiers
  • wos:000345282600103
  • scopus:84910681473
ISSN
0004-6361
DOI
10.1051/0004-6361/201425099
language
English
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yes
id
47457270-07bb-4c17-9760-b2f6a2ec9db4 (old id 5069054)
date added to LUP
2015-02-25 13:26:55
date last changed
2017-10-01 04:24:23
@article{47457270-07bb-4c17-9760-b2f6a2ec9db4,
  abstract     = {We performed a detailed study of the ratio of low-alpha to high-alpha stars in the Galactic halo as observed by the Gaia-ESO Survey. Using a sample of 381 metal-poor stars from the second internal data release, we found that the value of this ratio did not show evidence of systematic trends as a function of metallicity, surface gravity, Galactic latitude, Galactic longitude, height above the Galactic plane, and Galactocentric radius. We conclude that the alpha(poor)/alpha(rich) value of 0.28 +/- 0.08 suggests that in the inner halo, the larger portion of stars were formed in a high star formation rate environment, and about 15% of the metal-poor stars originated from much lower star formation rate environments.},
  articleno    = {L5},
  author       = {Jackson-Jones, R. and Jofre, P. and Hawkins, K. and Hourihane, A. and Gilmore, G. and Kordopatis, G. and Worley, C. and Randich, S. and Vallenari, A. and Bensby, Thomas and Bragaglia, A. and Flaccomio, E. and Korn, A. J. and Recio-Blanco, A. and Smiljanic, R. and Costado, M. T. and Heiter, U. and Hill, V. and Lardo, C. and de Laverny, P. and Guiglion, G. and Mikolaitis, S. and Zaggia, S. and Tautvaisiene, G.},
  issn         = {0004-6361},
  keyword      = {stars: abundances,Galaxy: halo},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {The Gaia-ESO Survey: alpha-abundances of metal-poor stars},
  url          = {http://dx.doi.org/10.1051/0004-6361/201425099},
  volume       = {571},
  year         = {2014},
}