The Gaia -ESO Survey: Lithium enrichment histories of the Galactic thick and thin disc

Research output: Contribution to journalArticle

Abstract

Lithium abundance in most of the warm metal-poor main sequence stars shows a constarnt plateau (A(Li) ~ 2.2 dex) and then the upper envelope of the lithium vs. metallicity distribution increases as we approach solar metallicity. Meteorites, which carry information about the chemical composition of the interstellar medium (ISM) at the solar system formation time, show a lithium abundance A(Li) ~ 3.26 dex. This pattern reflects the Li enrichment history of the ISM during the Galaxy lifetime. After the initial Li production in big bang nucleosynthesis, the sources of the enrichment include asymptotic giant branch (AGB) stars, low-mass red giants, novae, type II supernovae, and Galactic cosmic rays. The total amount of enriched Li is sensitive to the relative contribution of these sources. Thus different Li enrichment histories are expected in the Galactic thick and thin disc. We investigate the main sequence stars observed with UVES in Gaia-ESO Survey iDR4 catalogue and find a Li-anticorrelation independent of [Fe/H], Teff, and log(g). Since in stellar evolution different α enhancements at the same metallicity do not lead to a measurable Li abundance change, the anticorrelation indicates that more Li is produced during the Galactic thin disc phase than during the Galactic thick disc phase. We also find a correlation between the abundance of Li and s-process elements Ba and Y, and they both decrease above the solar metallicity, which can be explained in the framework of the adopted Galactic chemical evolution models.

Details

Authors
  • X. Fu
  • D. Romano
  • A. Bragaglia
  • A. Mucciarelli
  • K. Lind
  • E. Delgado Mena
  • S. G. Sousa
  • S. Randich
  • A. Bressan
  • L. Sbordone
  • S. Martell
  • A. J. Korn
  • C. Abia
  • R. Smiljanic
  • P. Jofré
  • E. Pancino
  • G. Tautvaišiene
  • B. Tang
  • L. Magrini
  • A. C. Lanzafame
  • G. Carraro
  • F. Damiani
  • E. J. Alfaro
  • E. Flaccomio
  • L. Morbidelli
  • S. Zaggia
  • C. Lardo
  • L. Monaco
  • A. Frasca
  • P. Donati
  • A. Drazdauskas
  • Y. Chorniy
  • A. Bayo
  • G. Kordopatis
Organisations
External organisations
  • INAF Osservatorio Astronomico di Bologna
  • Max Planck Institute for Astronomy
  • INAF - Osservatorio Astrofisico di Arcetri
  • International School For Advanced Studies (sissa/isas)
  • European Southern Observatory Santiago
  • University of New South Wales
  • Uppsala University
  • University of Granada
  • Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences
  • University of Cambridge
  • Diego Portales University
  • Vilnius University
  • University of Concepción
  • University of Catania
  • University of Padova
  • INAF Palermo Astronomical Observatory
  • CSIC Instituto de Astrofísica de Andalucía (IAA)
  • INAF - Osservatorio Astronomico di Padova
  • Swiss Federal Institute of Technology
  • Andrés Bello National University
  • Côte d'Azur Observatory
  • University of Bologna
  • University of Porto
  • University of Valparaíso
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology

Keywords

  • Galaxy: abundances, Galaxy: disk, Stars: abundances
Original languageEnglish
Article numberA38
JournalAstronomy and Astrophysics
Volume610
Publication statusPublished - 2018 Feb 1
Publication categoryResearch
Peer-reviewedYes