Bibcode
Magrini, L.; Spina, L.; Randich, S.; Friel, E.; Kordopatis, G.; Worley, C.; Pancino, E.; Bragaglia, A.; Donati, P.; Tautvaišienė, G.; Bagdonas, V.; Delgado-Mena, E.; Adibekyan, V.; Sousa, S. G.; Jiménez-Esteban, F. M.; Sanna, N.; Roccatagliata, V.; Bonito, R.; Sbordone, L.; Duffau, S.; Gilmore, G.; Feltzing, S.; Jeffries, R. D.; Vallenari, A.; Alfaro, E. J.; Bensby, T.; Francois, P.; Koposov, S.; Korn, A. J.; Recio-Blanco, A.; Smiljanic, R.; Bayo, A.; Carraro, G.; Casey, A. R.; Costado, M. T.; Damiani, F.; Franciosini, E.; Frasca, A.; Hourihane, A.; Jofré, P.; de Laverny, P.; Lewis, J.; Masseron, T.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Sacco, G.; Zaggia, S.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 617, id.A106, 15 pp.
Fecha de publicación:
9
2018
Revista
Número de citas
50
Número de citas referidas
48
Descripción
Context. Several works have found an increase of the abundances of the
s-process neutron-capture elements in the youngest Galactic stellar
populations. These trends provide important constraints on stellar and
Galactic evolution and they need to be confirmed with large and
statistically significant samples of stars spanning wide age and
distance intervals. Aims: We aim to trace the abundance patterns
and the time evolution of five s-process elements - two belonging to the
first peak, Y and Zr, and three belonging to the second peak, Ba, La,
and Ce - using the Gaia-ESO IDR5 results for open clusters and disc
stars. Methods: From the UVES spectra of cluster member stars, we
determined the average composition of clusters with ages >0.1 Gyr. We
derived statistical ages and distances of field stars, and we separated
them into thin and thick disc populations. We studied the time-evolution
and dependence on metallicity of abundance ratios using open clusters
and field stars whose parameters and abundances were derived in a
homogeneous way. Results: Using our large and homogeneous sample
of open clusters, thin and thick disc stars, spanning an age range
larger than 10 Gyr, we confirm an increase towards young ages of
s-process abundances in the solar neighbourhood. These trends are well
defined for open clusters and stars located nearby the solar position
and they may be explained by a late enrichment due to significant
contribution to the production of these elements from long-living
low-mass stars. At the same time, we find a strong dependence of the
s-process abundance ratios on the Galactocentric distance and on the
metallicity of the clusters and field stars. Conclusions: Our
results, derived from the largest and most homogeneous sample of
s-process abundances in the literature, confirm the growth with
decreasing stellar ages of the s-process abundances in both field and
open cluster stars. At the same time, taking advantage of the abundances
of open clusters located in a wide Galactocentric range, these results
offer a new perspective on the dependence of the s-process evolution on
the metallicity and star formation history, pointing to different
behaviours at various Galactocentric distances.
Based on observations collected with the FLAMES instrument at VLT/UT2
telescope (Paranal Observatory, ESO, Chile), for the Gaia-ESO Large
Public Spectroscopic Survey (188.B-3002, 193.B-0936).
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