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The Gaia -ESO Survey : Probing the lithium abundances in old metal-rich dwarf stars in the solar vicinity

Dantas, M. L.L. ; Guiglion, G. ; Smiljanic, R. ; Romano, D. ; Magrini, L. ; Bensby, T. LU orcid ; Chiappini, C. ; Franciosini, E. ; Nepal, S. and Tautvaišiene, G. , et al. (2022) In Astronomy and Astrophysics 668.
Abstract

Context. Lithium (Li) is a fragile element that is produced in a variety of sites but can also be very easily depleted in stellar photospheres. Radial migration has been reported to explain the decrease in the upper envelope of Li measurements observed for relatively old metal-rich dwarf stars in some surveys. Aims. We test a scenario in which radial migration could affect the Li abundance pattern of dwarf stars in the solar neighbourhood. This may confirm that the Li abundances in these stars cannot serve as a probe for the Li abundance in the interstellar medium (ISM). In other words, to probe the evolution of the Li abundance in the local ISM, it is crucial that stellar intruders be identified and removed from the adopted sample.... (More)

Context. Lithium (Li) is a fragile element that is produced in a variety of sites but can also be very easily depleted in stellar photospheres. Radial migration has been reported to explain the decrease in the upper envelope of Li measurements observed for relatively old metal-rich dwarf stars in some surveys. Aims. We test a scenario in which radial migration could affect the Li abundance pattern of dwarf stars in the solar neighbourhood. This may confirm that the Li abundances in these stars cannot serve as a probe for the Li abundance in the interstellar medium (ISM). In other words, to probe the evolution of the Li abundance in the local ISM, it is crucial that stellar intruders be identified and removed from the adopted sample. Methods. We used the high-quality data (including Li abundances) from the sixth internal Data Release of the Gaia-ESO survey. In this sample we grouped stars by similarity in chemical abundances via hierarchical clustering. Our analysis treats both measured Li abundances and upper limits. Results. The Li envelope of the previously identified radially migrated stars is well below the benchmark meteoritic value (<3.26 dex); the star with the highest detected abundance has A(Li) = 2.76 dex. This confirms the previous trends observed for old dwarf stars (median ages ~ 8 Gyr), where Li decreases for [Fe/H] ≳ 0. Conclusions. This result is supporting evidence that the abundance of Li measured in the upper envelope of old dwarf stars should not be considered a proxy for the ISM Li. Our scenario also indicates that the stellar yields for [M/H] >0 should not be decreased, as recently proposed in the literature. Our study backs recent studies that claim that old dwarfs on the hot side of the dip are efficient probes of the ISM abundance of Li, provided atomic diffusion does not significantly lower the initial Li abundance in the atmospheres of metal-rich objects.

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organization
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type
Contribution to journal
publication status
published
subject
keywords
Galaxy: abundances, Galaxy: evolution, Galaxy: stellar content, ISM: abundances, Stars: abundances
in
Astronomy and Astrophysics
volume
668
article number
L7
publisher
EDP Sciences
external identifiers
  • scopus:85145432449
ISSN
0004-6361
DOI
10.1051/0004-6361/202245230
language
English
LU publication?
yes
id
53354458-9316-4f0e-ba93-62069349aebe
date added to LUP
2023-01-16 15:58:02
date last changed
2024-04-17 21:33:13
@article{53354458-9316-4f0e-ba93-62069349aebe,
  abstract     = {{<p>Context. Lithium (Li) is a fragile element that is produced in a variety of sites but can also be very easily depleted in stellar photospheres. Radial migration has been reported to explain the decrease in the upper envelope of Li measurements observed for relatively old metal-rich dwarf stars in some surveys. Aims. We test a scenario in which radial migration could affect the Li abundance pattern of dwarf stars in the solar neighbourhood. This may confirm that the Li abundances in these stars cannot serve as a probe for the Li abundance in the interstellar medium (ISM). In other words, to probe the evolution of the Li abundance in the local ISM, it is crucial that stellar intruders be identified and removed from the adopted sample. Methods. We used the high-quality data (including Li abundances) from the sixth internal Data Release of the Gaia-ESO survey. In this sample we grouped stars by similarity in chemical abundances via hierarchical clustering. Our analysis treats both measured Li abundances and upper limits. Results. The Li envelope of the previously identified radially migrated stars is well below the benchmark meteoritic value (&lt;3.26 dex); the star with the highest detected abundance has A(Li) = 2.76 dex. This confirms the previous trends observed for old dwarf stars (median ages ~ 8 Gyr), where Li decreases for [Fe/H] ≳ 0. Conclusions. This result is supporting evidence that the abundance of Li measured in the upper envelope of old dwarf stars should not be considered a proxy for the ISM Li. Our scenario also indicates that the stellar yields for [M/H] &gt;0 should not be decreased, as recently proposed in the literature. Our study backs recent studies that claim that old dwarfs on the hot side of the dip are efficient probes of the ISM abundance of Li, provided atomic diffusion does not significantly lower the initial Li abundance in the atmospheres of metal-rich objects.</p>}},
  author       = {{Dantas, M. L.L. and Guiglion, G. and Smiljanic, R. and Romano, D. and Magrini, L. and Bensby, T. and Chiappini, C. and Franciosini, E. and Nepal, S. and Tautvaišiene, G. and Gilmore, G. and Randich, S. and Lanzafame, A. C. and Heiter, U. and Morbidelli, L. and Prisinzano, L. and Zaggia, S.}},
  issn         = {{0004-6361}},
  keywords     = {{Galaxy: abundances; Galaxy: evolution; Galaxy: stellar content; ISM: abundances; Stars: abundances}},
  language     = {{eng}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{The Gaia -ESO Survey : Probing the lithium abundances in old metal-rich dwarf stars in the solar vicinity}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/202245230}},
  doi          = {{10.1051/0004-6361/202245230}},
  volume       = {{668}},
  year         = {{2022}},
}