The Gaia-ESO Survey: alpha-abundances of metal-poor stars
2014 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 571, L5- p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2014. Vol. 571, L5- p.
stars: abundances, Galaxy: halo
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:uu:diva-245557DOI: 10.1051/0004-6361/201425099ISI: 000345282600103OAI: oai:DiVA.org:uu-245557DiVA: diva2:791413