Chemical abundances in the ancient Milky Way: G-type SDSS stars. Automated determination of T_{eff}, log g, [Fe/H] and [alpha /F]
GIRARD, Pascal
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
SOUBIRAN, C.
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
GIRARD, Pascal
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
SOUBIRAN, C.
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
< Reduce
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
Language
en
Article de revue
This item was published in
Memorie della Societa astronomica italiana. 2006, vol. 77, p. 1173
Società astronomica italiana
English Abstract
We have developed TGMETalpha in order to determine T_{eff}, log g, [Fe/H] and [alpha /Fe] for large samples of FGK stars observed at various spectral resolutions. Tests on several hundred echelle spectra of reference stars ...Read more >
We have developed TGMETalpha in order to determine T_{eff}, log g, [Fe/H] and [alpha /Fe] for large samples of FGK stars observed at various spectral resolutions. Tests on several hundred echelle spectra of reference stars degraded to low resolution (R=1.000) indicate typical rms precisions of sigma (T_{eff})˜150 K, sigma (logg)˜0.44, sigma ([Fe/H])˜0.15 and sigma ([alpha /Fe])˜0.06. We have used TGMETalpha to determine atmospheric parameters and alpha -abundances from ˜15000 SDSS stellar spectra. Thanks to this very large sample we have investigated the vertical, radial and rotational properties as well as the abundance ratio of alpha elements to iron, [alpha /Fe], of samples representative of the thick disk and the halo. Results presented in the poster, provide new constraints on galactic thick disk formation models. We find evidence for a strong negative radial gradient in [alpha /Fe] with a lack or small one in [Fe/H] in the thick disk. Moreover, there is a lack of vertical gradient in both [Fe/H] and [alpha /Fe]. These features have to be reconciled with the timescale of the thick disk formation as well as with the SFR, IMF, infall of gas or accreted satellite debris.Read less <
English Keywords
Thick Disk
Stars: Galactic Halo
Stars: fundamental parameters
abundances
Galaxy: structure
Galaxy: stellar content
Origin
Hal imported