Volume 592, August 2016
|Number of page(s)||12|
|Published online||03 August 2016|
1 Instituto de Astrofísica e Ciências
do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762
2 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
3 Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
4 Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
5 Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
6 Byurakan Astrophysical Observatory, 0213 Byurakan, Aragatsotn province, Armenia
Accepted: 6 June 2016
Context. During the past decade, several studies reported a correlation between chemical abundances of stars and condensation temperature (also known as Tc trend). However, the real astrophysical nature of this correlation is still debated.
Aims. The main goal of this work is to explore the possible dependence of the Tc trend on stellar Galactocentric distances, Rmean.
Methods. We used high-quality spectra of about 40 stars observed with the HARPS and UVES spectrographs to derive precise stellar parameters, chemical abundances, and stellar ages. A differential line-by-line analysis was applied to achieve the highest possible precision in the chemical abundances.
Results. We confirm previous results that [X/Fe] abundance ratios depend on stellar age and that for a given age, some elements also show a dependence on Rmean. When using the whole sample of stars, we observe a weak hint that the Tc trend depends on Rmean. The observed dependence is very complex and disappears when only stars with similar ages are considered.
Conclusions. To conclude on the possible dependence of the Tc trend on the formation place of stars, a larger sample of stars with very similar atmospheric parameters and stellar ages observed at different Galactocentric distances is needed.
Key words: techniques: spectroscopic / stars: abundances / stars: atmospheres / Galaxy: disk / Galaxy: evolution
Based on observations collected with the HARPS spectrograph at the 3.6-m telescope (program ID: 095.D-0717(A)), installed at the La Silla Observatory, ESO (Chile), with the UVES spectrograph at the 8-m Very Large Telescope (program ID: 095.D-0717(B)), installed at the Cerro Paranal Observatory, ESO (Chile). Also based on data obtained from the ESO Science Archive Facility under request numbers: vadibekyan180760, vadibekyan180762, vadibekyan180764, vadibekyan180768, vadibekyan180769, vadibekyan180771, vadibekyan180773, vadibekyan180778, and vadibekyan180779.
Tables with stellar parameters and chemical abundances are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (126.96.36.199) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A87
© ESO, 2016
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