| Texto completo | |
| Autor(es): |
Bensby, T.
[1]
;
Feltzing, S.
[1]
;
Yee, J. C.
[2]
;
Johnson, J. A.
[3]
;
Gould, A.
[3, 4, 5]
;
Asplund, M.
[6]
;
Melendez, J.
[7]
;
Lucatello, S.
[8]
Número total de Autores: 8
|
| Afiliação do(s) autor(es): | [1] Lund Observ, Dept Astron & Theoret Phys, Box 43, S-22100 Lund - Sweden
[2] Harvard & Smithsonian, Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 - USA
[3] Ohio State Univ, Dept Astron, 174 W 18Th Ave, Columbus, OH 43210 - USA
[4] Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg - Germany
[5] Korea Astron & Space Sci Inst Inst, Daejon 305348 - South Korea
[6] Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Cotter Rd, Weston, ACT 2611 - Australia
[7] Univ Sao Paulo, Dept Astron IAG, Rua Matao 1226, BR-05508900 Sao Paulo, SP - Brazil
[8] Astron Observ Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua - Italy
Número total de Afiliações: 8
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Astronomy & Astrophysics; v. 634, FEB 25 2020. |
| Citações Web of Science: | 0 |
| Resumo | |
Lithium abundances are presented for 91 dwarf and subgiant stars in the Galactic bulge. The analysis is based on line synthesis of the Li-7 line at 6707 angstrom in high-resolution spectra obtained during gravitational microlensing events, when the brightnesses of the targets were highly magnified. Our main finding is that bulge stars at sub-solar metallicities that are older than about eight billion years do not show any sign of Li production; that is, the Li trend with metallicity is flat or even slightly declining. This indicates that no lithium was produced during the first few billion years in the history of the bulge. This finding is essentially identical to what is seen for the (old) thick disk stars in the solar neighbourhood, and adds another piece of evidence for a tight connection between the metal-poor bulge and the Galactic thick disk. For the bulge stars younger than about eight billion years, the sample contains a group of stars at very high metallicities at {[}Fe/H];approximate to;+0.4 that have lithium abundances in the range A(Li);=;2.6 - 2.8. In the solar neighbourhood the lithium abundances have been found to peak at A(Li);approximate to;3.3 at {[}Fe/H];approximate to;+0.1 and then decrease by 0.4-0.5 dex when reaching {[}Fe/H];approximate to;+0.4. The few bulge stars that we have at these metallicities seem to support this declining A(Li) trend. This could indeed support the recent claim that the low A(Li) abundances at the highest metallicities seen in the solar neighbourhood could be due to stars from the inner disk, or the bulge region, that have migrated to the solar neighbourhood. (AU) | |
| Processo FAPESP: | 14/18100-4 - Populações estelares na Via Láctea: bojo, halo, disco e regiões de formação de estrelas; instrumentação para espectroscopia de alta resolução |
| Beneficiário: | Beatriz Leonor Silveira Barbuy |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |