| Texto completo | |
| Autor(es): |
Número total de Autores: 5
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| Afiliação do(s) autor(es): | [1] Lund Observ, Dept Astron & Theoret Phys, SE-22100 Lund - Sweden
[2] Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago - Chile
[3] Univ Michigan, Dept Astron, Ann Arbor, MI 48109 - USA
[4] Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611 - Australia
[5] Univ Sao Paulo, Dept Astron IAG USP, BR-05508900 Sao Paulo - Brazil
Número total de Afiliações: 5
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| Tipo de documento: | Artigo Científico |
| Fonte: | Astrophysical Journal Letters; v. 735, n. 2 JUL 10 2011. |
| Citações Web of Science: | 117 |
| Resumo | |
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. (AU) | |
| Processo FAPESP: | 10/50930-6 - Evolução química e populações estelares galácticas e extragalácticas, por espectroscopia e imageamento |
| Beneficiário: | Beatriz Leonor Silveira Barbuy |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |