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The Gaia -ESO survey : Age-chemical-clock relations spatially resolved in the Galactic disc

Viscasillas Vázquez, C. ; Magrini, L. ; Casali, G. ; Tautvaišiene, G. ; Spina, L. ; Van Der Swaelmen, M. ; Randich, S. ; Bensby, T. LU orcid ; Bragaglia, A. and Friel, E. , et al. (2022) In Astronomy and Astrophysics 660.
Abstract

Context. The last decade has seen a revolution in our knowledge of the Galaxy thanks to the Gaia and asteroseismic space missions and the ground-based spectroscopic surveys. Aims. To complete this picture, it is necessary to map the ages of its stellar populations. During recent years, the dependence on time of abundance ratios involving slow (s) neutron-capture and α elements (called chemical-clocks) has been used to provide estimates of stellar ages, usually in a limited volume close to the Sun. We aim to analyse the relations of chemical clocks in the Galactic disc extending the range to RGC∼ 6- 20 kpc. Methods. Using the sixth internal data release of the Gaia-ESO survey, we calibrated several relations between stellar ages and... (More)

Context. The last decade has seen a revolution in our knowledge of the Galaxy thanks to the Gaia and asteroseismic space missions and the ground-based spectroscopic surveys. Aims. To complete this picture, it is necessary to map the ages of its stellar populations. During recent years, the dependence on time of abundance ratios involving slow (s) neutron-capture and α elements (called chemical-clocks) has been used to provide estimates of stellar ages, usually in a limited volume close to the Sun. We aim to analyse the relations of chemical clocks in the Galactic disc extending the range to RGC∼ 6- 20 kpc. Methods. Using the sixth internal data release of the Gaia-ESO survey, we calibrated several relations between stellar ages and abundance ratios [s/α] using a sample of open clusters, the largest one so far used with this aim (62 clusters). Thanks to their wide galactocentric coverage, we investigated the radial variations of the shape of these relations, confirming their non-universality. Results. The multi-variate relations allowed us to infer stellar ages for field stars. We estimated our accuracy (ranging from 0.0 to -0.9 Gyr) and precision (from 0.4 to 2.3 Gyr) in recovering the global ages of open clusters, and the ages of their individual members. We applied the relations with the highest correlation coefficients to the field star population, finding an older population at lower metallicity and higher [α/Fe] in the thin disc, and a younger one at higher [Fe/H] and low [α/Fe], as expected. Conclusion. We confirm that there is no single age-chemical clock relationship valid for the whole disc, but that there is a dependence on the galactocentric position, which is related to the radial variation of the star formation history combined with the non-monotonic dependence on metallicity of the yields of the s-process elements from low- and intermediate-mass stars. Finally, the abundance ratios [Ba/α] are more sensitive to age than those with [Y/α] for young disc stars, and their slopes vary less with galactocentric distance. We remind the reader that the application of such relationships to field stars is only of statistical value.

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type
Contribution to journal
publication status
published
subject
keywords
Galaxy: abundances, Galaxy: disk, Open clusters and associations: general, Stars: abundances
in
Astronomy and Astrophysics
volume
660
article number
A135
publisher
EDP Sciences
external identifiers
  • scopus:85129229412
ISSN
0004-6361
DOI
10.1051/0004-6361/202142937
language
English
LU publication?
yes
id
412dc799-f4cf-4f07-88bc-a148ca92fa15
date added to LUP
2022-08-15 15:43:01
date last changed
2024-04-18 13:09:57
@article{412dc799-f4cf-4f07-88bc-a148ca92fa15,
  abstract     = {{<p>Context. The last decade has seen a revolution in our knowledge of the Galaxy thanks to the Gaia and asteroseismic space missions and the ground-based spectroscopic surveys. Aims. To complete this picture, it is necessary to map the ages of its stellar populations. During recent years, the dependence on time of abundance ratios involving slow (s) neutron-capture and α elements (called chemical-clocks) has been used to provide estimates of stellar ages, usually in a limited volume close to the Sun. We aim to analyse the relations of chemical clocks in the Galactic disc extending the range to RGC∼ 6- 20 kpc. Methods. Using the sixth internal data release of the Gaia-ESO survey, we calibrated several relations between stellar ages and abundance ratios [s/α] using a sample of open clusters, the largest one so far used with this aim (62 clusters). Thanks to their wide galactocentric coverage, we investigated the radial variations of the shape of these relations, confirming their non-universality. Results. The multi-variate relations allowed us to infer stellar ages for field stars. We estimated our accuracy (ranging from 0.0 to -0.9 Gyr) and precision (from 0.4 to 2.3 Gyr) in recovering the global ages of open clusters, and the ages of their individual members. We applied the relations with the highest correlation coefficients to the field star population, finding an older population at lower metallicity and higher [α/Fe] in the thin disc, and a younger one at higher [Fe/H] and low [α/Fe], as expected. Conclusion. We confirm that there is no single age-chemical clock relationship valid for the whole disc, but that there is a dependence on the galactocentric position, which is related to the radial variation of the star formation history combined with the non-monotonic dependence on metallicity of the yields of the s-process elements from low- and intermediate-mass stars. Finally, the abundance ratios [Ba/α] are more sensitive to age than those with [Y/α] for young disc stars, and their slopes vary less with galactocentric distance. We remind the reader that the application of such relationships to field stars is only of statistical value. </p>}},
  author       = {{Viscasillas Vázquez, C. and Magrini, L. and Casali, G. and Tautvaišiene, G. and Spina, L. and Van Der Swaelmen, M. and Randich, S. and Bensby, T. and Bragaglia, A. and Friel, E. and Feltzing, S. and Sacco, G. G. and Turchi, A. and Jiménez-Esteban, F. and D'Orazi, V. and Delgado-Mena, E. and Mikolaitis and Drazdauskas, A. and Minkevičiūte, R. and Stonkute, E. and Bagdonas, V. and Montes, D. and Guiglion, G. and Baratella, M. and Tabernero, H. M. and Gilmore, G. and Alfaro, E. and Francois, P. and Korn, A. and Smiljanic, R. and Bergemann, M. and Franciosini, E. and Gonneau, A. and Hourihane, A. and Worley, C. C. and Zaggia, S.}},
  issn         = {{0004-6361}},
  keywords     = {{Galaxy: abundances; Galaxy: disk; Open clusters and associations: general; Stars: abundances}},
  language     = {{eng}},
  month        = {{04}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{The Gaia -ESO survey : Age-chemical-clock relations spatially resolved in the Galactic disc}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/202142937}},
  doi          = {{10.1051/0004-6361/202142937}},
  volume       = {{660}},
  year         = {{2022}},
}