Lithium-rich giants in the Galactic thick disk
Astronomy & Astrophysics
| dc.creator | Monaco, L. | |
| dc.creator | Villanova, S. | |
| dc.creator | Moni Bidin, C. | |
| dc.creator | Geisler, D. | |
| dc.creator | Zoccali, M. | |
| dc.date | 2019-12-18T18:15:14Z | |
| dc.date | 2022-07-07T23:39:59Z | |
| dc.date | 2019-12-18T18:15:14Z | |
| dc.date | 2022-07-07T23:39:59Z | |
| dc.date | 2011 | |
| dc.date.accessioned | 2023-08-21T20:54:28Z | |
| dc.date.available | 2023-08-21T20:54:28Z | |
| dc.identifier | 15010003 | |
| dc.identifier | 15010003 | |
| dc.identifier | https://hdl.handle.net/10533/237321 | |
| dc.identifier.uri | https://repositorioslatinoamericanos.uchile.cl/handle/2250/8281085 | |
| dc.description | Context: Lithium is a fragile element, which is easily destroyed in the stellar interior. The existence of lithium-rich giants still represents a challenge for stellar evolution models. Aims: We have collected a large database of high-resolution stellar spectra of 824 candidate thick-disk giants having 2\,MASS photometry and proper motions measured by the Southern Proper-Motion Program (SPM). In order to investigate the nature of Li-rich giants, we searched this database for giants presenting a strong Li\,I resonance line. Methods: We performed a chemical abundance analysis on the selected stars with the MOOG code along with proper ATLAS-9 model atmospheres. The iron content and atmospheric parameters were fixed by using the equivalent width of a sample of Fe lines. We also derive abundances for C, N, and O and measure or derive lower limits on the 12C/13C isotopic ratios, which is a sensible diagnostic of the stars evolutionary status. Results: We detected five stars with a lithium abundance higher than 1.5, i.e. Li-rich according to the current definition. One of them (SPM-313132) has A(Li)>3.3 and, because of this, belongs to the group of the rare super Li-rich giants. Its kinematics makes it a likely thin-disk member and its atmospheric parameters are compatible with it being a 4\,M⊙ star either on the red giant branch (RGB) or the early asymptotic giant branch. This object is the first super Li-rich giant detected at this phase. The other four are likely low-mass thick-disk stars evolved past the RGB luminosity bump, as determined from their metallicities and atmospheric parameters. The most evolved of them lies close to the RGB-tip. It has A(Li)>2.7 and a low 12C/13C isotopic ratio, close to the cool bottom processing predictions. | |
| dc.description | FONDAP | |
| dc.description | FONDAP | |
| dc.language | eng | |
| dc.relation | instname: Conicyt | |
| dc.relation | reponame: Repositorio Digital RI2.0 | |
| dc.relation | info:eu-repo/grantAgreement/Fondap/15010003 | |
| dc.relation | https://arxiv.org/abs/1103.1658 | |
| dc.rights | Atribución-NoComercial-SinDerivadas 3.0 Chile | |
| dc.rights | http://creativecommons.org/licenses/by-nc-nd/3.0/cl/ | |
| dc.rights | info:eu-repo/semantics/openAccess | |
| dc.title | Lithium-rich giants in the Galactic thick disk | |
| dc.title | Astronomy & Astrophysics | |
| dc.type | Articulo | |
| dc.type | info:eu-repo/semantics/article | |
| dc.type | info:eu-repo/semantics/publishedVersion |