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

Titulo: 
The Gaia-ESO Survey: alpha-abundances of metal-poor stars
Autores: 
Jackson-Jones, R; Jofre, P; Hawkins, K; Hourihane, A; Gilmore, G; Kordopatis, G; Worley, C; Randich, S; Vallenari, A; Bensby, T; Bragaglia, A; Flaccomio, E; Korn, AJ; Recio-Blanco, A; Smiljanic, R; Costado, MT; Heiter, U; Hill, V; Lardo, C; de Laverny, P; Guiglion, G; Mikolaitis, S; Zaggia, S; Tautvaisiene, G
Resumen: 
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.
Autor principal: 
Jackson-Jones, R
Autor/es del IAA: 
Costado, M. T.
DOI: 
10.1051/0004-6361/201425099
Revista: 
ASTRONOMY & ASTROPHYSICS
Fecha de publicación: 
2014/11
Volumen: 
571
Tipo de documento: 
Article
Palabras clave: 
stars: abundances; Galaxy: halo
Número de artículo: 
L5