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Vertical distribution of Galactic disk stars IV - AMR and AVR from clump giants

Authors :
Caroline Soubiran
V. V. Kovtyukh
T. V. Mishenina
Olivier Bienaymé
Observatoire aquitain des sciences de l'univers (OASU)
Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB)
Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB)
Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Observatoire astronomique de Strasbourg (OAS)
Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)
Astronomical observatory of Odessa National University [Odessa]
Odessa National I.I.Mechnikov University
Odessa Astronomical Observatory
Source :
Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2008, 480, pp.91-101. ⟨10.1051/0004-6361:20078788⟩
Publication Year :
2008
Publisher :
HAL CCSD, 2008.

Abstract

We present the parameters of 891 stars, mostly clump giants, including atmospheric parameters, distances, absolute magnitudes, spatial velocities, galactic orbits and ages. One part of this sample consists of local giants, within 100 pc, with atmospheric parameters either estimated from our spectroscopic observations at high resolution and high signal-to-noise ratio, or retrieved from the literature. The other part of the sample includes 523 distant stars, which we have estimated atmospheric parameters from high resolution but low signal-to-noise Echelle spectra. This new sample is kinematically unbiased, with well-defined boundaries in magnitude and colours. We revisit the basic properties of the Galactic thin disk as traced by clump giants. We find the metallicity distribution to be different from that of dwarfs, with less metal-rich stars. We find evidence for a vertical metallicity gradient of -0.31 dex/kpc and for a transition at 4-5 Gyr in both the metallicity and velocities. The age - metallicity relation (AMR), which exhibits a very low dispersion, increases smoothly from 10 to 4 Gyr, with a steeper increase for younger stars. The age-velocity relation (AVR) is characterized by the saturation of the V and W dispersions at 5 Gyr, and continuous heating in U.<br />Comment: 13 pages, 14 figures, accepted in A&A

Details

Language :
English
ISSN :
00046361
Database :
OpenAIRE
Journal :
Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2008, 480, pp.91-101. ⟨10.1051/0004-6361:20078788⟩
Accession number :
edsair.doi.dedup.....295940ba12c9685fddea58059c1fb166
Full Text :
https://doi.org/10.1051/0004-6361:20078788⟩