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The Gaia -ESO Survey : No sign of multiple stellar populations in open clusters from their sodium and oxygen abundances

Bragaglia, A. ; D'Orazi, V. ; Magrini, L. ; Baratella, M. ; Bensby, T. LU orcid ; Martell, S. L. ; Randich, S. ; Tautvaišiene, G. ; Alfaro, E. J. and Morbidelli, L. , et al. (2024) In Astronomy and Astrophysics 687.
Abstract

Context. The light element (anti-)correlations shown by globular clusters (GCs) are the main spectroscopic signature of multiple stellar populations. These internal abundance variations provide us with fundamental constraints on the formation mechanism of stellar clusters. Aims. Using Gaia-ESO, the largest and most homogeneous survey of open clusters (OCs), we intend to check whether these stellar aggregates display the same patterns. Based on previous studies of many GCs, several young and massive clusters in the Magellanic Clouds, as well as a few OCs, we do not expect to find any anti-correlation, given the low mass of Milky Way OCs. Methods. We used the results based on UVES spectra of stars in Gaia-ESO to derive the distribution of... (More)

Context. The light element (anti-)correlations shown by globular clusters (GCs) are the main spectroscopic signature of multiple stellar populations. These internal abundance variations provide us with fundamental constraints on the formation mechanism of stellar clusters. Aims. Using Gaia-ESO, the largest and most homogeneous survey of open clusters (OCs), we intend to check whether these stellar aggregates display the same patterns. Based on previous studies of many GCs, several young and massive clusters in the Magellanic Clouds, as well as a few OCs, we do not expect to find any anti-correlation, given the low mass of Milky Way OCs. Methods. We used the results based on UVES spectra of stars in Gaia-ESO to derive the distribution of Na and O abundances and see whether they show an unexplained dispersion or whether they are anti-correlated. By selecting only high-probability members with high-precision stellar parameters, we ended up with more than 700 stars in 74 OCs. We examined the O-Na distribution in 28 OCs with at least 4 stars available as well as the Na distribution in 24 OCs, with at least 10 stars available. Results. We find that the distribution of Na abundances is compatible with a single-value population, within the errors. The few apparent exceptions can be explained by differences in the evolutionary phase (main sequence and giant post first dredge-up episode) or by difficulties in analysing low gravity giants. We did not find any indication of an Na-O anti-correlation in any of the clusters for which O has been derived. Conclusions. Based on the very small spread we find, OCs maintain the status of single stellar populations. However, a definitive answer requires studying more elements and larger samples covering different evolutionary phases. This will be possible with the next generation of large surveys.

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organization
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type
Contribution to journal
publication status
published
subject
keywords
Open clusters and associations: general, Stars: abundances, Stars: kinematics and dynamics, Techniques: radial velocities, Techniques: spectroscopic
in
Astronomy and Astrophysics
volume
687
article number
A124
publisher
EDP Sciences
external identifiers
  • scopus:85197546039
ISSN
0004-6361
DOI
10.1051/0004-6361/202245144
language
English
LU publication?
yes
id
8c557358-dfaf-409d-bce5-65ea2bc10884
date added to LUP
2024-10-09 15:47:32
date last changed
2025-04-04 15:04:18
@article{8c557358-dfaf-409d-bce5-65ea2bc10884,
  abstract     = {{<p>Context. The light element (anti-)correlations shown by globular clusters (GCs) are the main spectroscopic signature of multiple stellar populations. These internal abundance variations provide us with fundamental constraints on the formation mechanism of stellar clusters. Aims. Using Gaia-ESO, the largest and most homogeneous survey of open clusters (OCs), we intend to check whether these stellar aggregates display the same patterns. Based on previous studies of many GCs, several young and massive clusters in the Magellanic Clouds, as well as a few OCs, we do not expect to find any anti-correlation, given the low mass of Milky Way OCs. Methods. We used the results based on UVES spectra of stars in Gaia-ESO to derive the distribution of Na and O abundances and see whether they show an unexplained dispersion or whether they are anti-correlated. By selecting only high-probability members with high-precision stellar parameters, we ended up with more than 700 stars in 74 OCs. We examined the O-Na distribution in 28 OCs with at least 4 stars available as well as the Na distribution in 24 OCs, with at least 10 stars available. Results. We find that the distribution of Na abundances is compatible with a single-value population, within the errors. The few apparent exceptions can be explained by differences in the evolutionary phase (main sequence and giant post first dredge-up episode) or by difficulties in analysing low gravity giants. We did not find any indication of an Na-O anti-correlation in any of the clusters for which O has been derived. Conclusions. Based on the very small spread we find, OCs maintain the status of single stellar populations. However, a definitive answer requires studying more elements and larger samples covering different evolutionary phases. This will be possible with the next generation of large surveys.</p>}},
  author       = {{Bragaglia, A. and D'Orazi, V. and Magrini, L. and Baratella, M. and Bensby, T. and Martell, S. L. and Randich, S. and Tautvaišiene, G. and Alfaro, E. J. and Morbidelli, L. and Smiljanic, R. and Zaggia, S.}},
  issn         = {{0004-6361}},
  keywords     = {{Open clusters and associations: general; Stars: abundances; Stars: kinematics and dynamics; Techniques: radial velocities; Techniques: spectroscopic}},
  language     = {{eng}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{The Gaia -ESO Survey : No sign of multiple stellar populations in open clusters from their sodium and oxygen abundances}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/202245144}},
  doi          = {{10.1051/0004-6361/202245144}},
  volume       = {{687}},
  year         = {{2024}},
}