%0 Journal Article
%T The Gaia-ESO Survey: ¦Á-abundances of metal-poor stars
%A R. Jackson-Jones
%A P. Jofr¨¦
%A K. Hawkins
%A A. Hourihane
%A G. Gilmore
%A G. Kordopatis
%A C. Worley
%A S. Randich
%A A. Vallenari
%A T. Bensby
%A A. Bragaglia
%A E. Flaccomio
%A A. J. Korn
%A A. Recio-Blanco
%A R. Smiljanic
%A M. T. Costado
%A U. Heiter
%A V. Hill
%A C. Lardo
%A P. de Laverny
%A G. Guiglion
%A S. Mikolaitis
%A S. Zaggia
%A G. Tautvai£¿iene
%J Physics
%D 2014
%I arXiv
%R 10.1051/0004-6361/201425099
%X 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 $\pm$ 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.
%U http://arxiv.org/abs/1410.6415v1