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The Gaia-ESO survey : radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk

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The Gaia-ESO survey : radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk

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Título The Gaia-ESO survey : radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk
Autor Bergemann, Maria
Ruchti, Gregory
Serenelli, Aldo M.
Feltzing, Sofia
Brito, Alan Alves
Asplund, Martin
Bensby, Thomas L.
Gruyters, Pieter
Heiter, Ulrike
Hourihane, Anna
Korn, Andreas J.
Lind, Karin
Marino, Anna
Jofre, Paula
Nordlander, Thomas
Ryde, Nils A. E.
Worley, Clare C.
Gilmore, Gerard Fitzgerald
Randich, Sofia
Ferguson, Annette M. N.
Jeffries, Rob D.
Micela, Giuseppina
Negueruela, Ignacio
Prusti, Timo
Rix, H.-W.
Vallenari, Antonella
Alfaro, Emilio Javier
Allende Prieto, Carlos
Bragaglia, Angela
Koposov, Sergey E.
Lanzafame, Alessandro C.
Pancino, Elena
Recio-Blanco, Alejandra
Smiljanic, Rodolfo Henrique Silva
Walton, Nicholas A.
Costado, María Teresa
Franciosini, Elena
Hill, Vanessa
Lardo, Carmela
De Laverny, Patrick‏
Magrini, Laura
Maiorca, Enrico
Masseron, Thomas
Morbidelli, Lorenzo
Sacco, Germano
Kordopatis, Georges
Tautvaišiene, Gražina
Abstract We study the relationship between age, metallicity, and α-enhancement of FGK stars in the Galactic disk. The results are based upon the analysis of high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore the limitations of the observed dataset, i.e. the accuracy of stellar parameters and the selection effects that are caused by the photometric target preselection. We find that the colour and magnitude cuts in the survey suppress old metal-rich stars and young metal-poor stars. This suppression may be as high as 97% in some regions of the age-metallicity relationship. The dataset consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5 Gyr, Galactocentric distances from 6 kpc to 9.5 kpc, and vertical distances from the plane 0 < |Z| < 1.5 kpc. On this basis, we find that i) the observed age-metallicity relation is nearly flat in the range of ages between 0 Gyr and 8 Gyr; ii) at ages older than 9 Gyr, we see a decrease in [Fe/H] and a clear absence of metal-rich stars; this cannot be explained by the survey selection functions; iii) there is a significant scatter of [Fe/H] at any age; and iv) [Mg/Fe] increases with age, but the dispersion of [Mg/Fe] at ages >9 Gyr is not as small as advocated by some other studies. In agreement with earlier work, we find that radial abundance gradients change as a function of vertical distance from the plane. The [Mg/Fe] gradient steepens and becomes negative. In addition, we show that the inner disk is not only more α-rich compared to the outer disk, but also older, as traced independently by the ages and Mg abundances of stars.
Contido em Astronomy and astrophysics. Les Ulis. Vol. 565 (May 2014), A89, 11 p.
Assunto Astronomia ultravioleta
Composicao estelar
Espectros estelares
Galaxia
Mapeamentos astronômicos
[en] Abundances
[en] Disk
[en] Formation
[en] Fundamental parameters
[en] Galaxy
[en] Solar neighborhood
[en] Stars
[en] Surveys
Origem Estrangeiro
Tipo Artigo de periódico
URI http://hdl.handle.net/10183/118048
Arquivos Descrição Formato
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