Advanced

A First Constraint on the Thick Disk Scale Length: Differential Radial Abundances in K Giants at Galactocentric Radii 4, 8, and 12 kpc

Bensby, Thomas LU ; Alves-Brito, A.; Oey, M. S.; Yong, D. and Melendez, J. (2011) In Astrophysical Journal Letters 735(2).
Abstract
Based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes, we present detailed elemental abundances for 20 red giant stars in the outer Galactic disk, located at Galactocentric distances between 9 and 13 kpc. The outer disk sample is complemented with samples of red giants from the inner Galactic disk and the solar neighborhood, analyzed using identical methods. For Galactocentric distances beyond 10 kpc, we only find chemical patterns associated with the local thin disk, even for stars far above the Galactic plane. Our results show that the relative densities of the thick and thin disks are dramatically different from the solar neighborhood, and we therefore suggest that the radial scale length of the... (More)
Based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes, we present detailed elemental abundances for 20 red giant stars in the outer Galactic disk, located at Galactocentric distances between 9 and 13 kpc. The outer disk sample is complemented with samples of red giants from the inner Galactic disk and the solar neighborhood, analyzed using identical methods. For Galactocentric distances beyond 10 kpc, we only find chemical patterns associated with the local thin disk, even for stars far above the Galactic plane. Our results show that the relative densities of the thick and thin disks are dramatically different from the solar neighborhood, and we therefore suggest that the radial scale length of the thick disk is much shorter than that of the thin disk. We make a first estimate of the thick disk scale length of L-thick = 2.0 kpc, assuming L-thin = 3.8 kpc for the thin disk. We suggest that radial migration may explain the lack of radial age, metallicity, and abundance gradients in the thick disk, possibly also explaining the link between the thick disk and the metal-poor bulge. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Galaxy: abundances, Galaxy: disk, Galaxy: evolution, Galaxy: formation, Galaxy: stellar content, stars: abundances
in
Astrophysical Journal Letters
volume
735
issue
2
publisher
University of Chicago Press
external identifiers
  • wos:000293138000022
  • scopus:79960922750
ISSN
2041-8213
DOI
10.1088/2041-8205/735/2/L46
language
English
LU publication?
yes
id
d2bf261c-7d7d-4aa2-875c-f755d709297b (old id 2072469)
date added to LUP
2011-08-26 09:04:07
date last changed
2017-11-12 03:11:38
@article{d2bf261c-7d7d-4aa2-875c-f755d709297b,
  abstract     = {Based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes, we present detailed elemental abundances for 20 red giant stars in the outer Galactic disk, located at Galactocentric distances between 9 and 13 kpc. The outer disk sample is complemented with samples of red giants from the inner Galactic disk and the solar neighborhood, analyzed using identical methods. For Galactocentric distances beyond 10 kpc, we only find chemical patterns associated with the local thin disk, even for stars far above the Galactic plane. Our results show that the relative densities of the thick and thin disks are dramatically different from the solar neighborhood, and we therefore suggest that the radial scale length of the thick disk is much shorter than that of the thin disk. We make a first estimate of the thick disk scale length of L-thick = 2.0 kpc, assuming L-thin = 3.8 kpc for the thin disk. We suggest that radial migration may explain the lack of radial age, metallicity, and abundance gradients in the thick disk, possibly also explaining the link between the thick disk and the metal-poor bulge.},
  articleno    = {L46},
  author       = {Bensby, Thomas and Alves-Brito, A. and Oey, M. S. and Yong, D. and Melendez, J.},
  issn         = {2041-8213},
  keyword      = {Galaxy: abundances,Galaxy: disk,Galaxy: evolution,Galaxy: formation,Galaxy: stellar content,stars: abundances},
  language     = {eng},
  number       = {2},
  publisher    = {University of Chicago Press},
  series       = {Astrophysical Journal Letters},
  title        = {A First Constraint on the Thick Disk Scale Length: Differential Radial Abundances in K Giants at Galactocentric Radii 4, 8, and 12 kpc},
  url          = {http://dx.doi.org/10.1088/2041-8205/735/2/L46},
  volume       = {735},
  year         = {2011},
}