The GALAH survey: accreted stars also inhabit the Spite plateau
Article
Article Title | The GALAH survey: accreted stars also inhabit the Spite plateau |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Simpson, Jeffrey D. (Author), Martell, Sarah L. (Author), Buder, Sven (Author), Bland-Hawthorn, Joss (Author), Casey, Andrew R. (Author), De Silva, Gayandhi M. (Author), D'Orazi, Valentina (Author), Freeman, Ken C. (Author), Hayden, Michael (Author), Kos, Janez (Author), Lewis, Geraint F. (Author), Lind, Karin (Author), Schlesinger, Katharine J. (Author), Sharma, Sanjib (Author), Stello, Dennis (Author), Zucker, Daniel B. (Author), Zwitter, Tomaz (Author), Asplund, Martin (Author), Da Costa, Gary (Author), Cotar, Klemen (Author), Tepper-Garcia, Thor (Author), Horner, Jonathan (Author), Nordlander, Thomas (Author), Ting, Yuan-Sen (Author) and Wyse, Rosemary F. G. (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 507 (1), pp. 43-54 |
Number of Pages | 12 |
Year | 2021 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/stab2012 |
Web Address (URL) | https://academic.oup.com/mnras/article/507/1/43/6321839 |
Abstract | The European Space Agency (ESA) Gaia mission has enabled the remarkable discovery that a large fraction of the stars near the solar neighbourhood are debris from a single in-falling system, the so-called Gaia-Sausage-Enceladus (GSE). This discovery provides astronomers for the first time with a large cohort of easily observable, unevolved stars that formed in a single extragalactic environment. Here we use these stars to investigate the 'Spite plateau' - the near-constant lithium abundance observed in unevolved metal-poor stars across a wide range of metallicities (-3 < [Fe/H] < -1). Our aim is to test whether individual galaxies could have different Spite plateaus - e.g. the interstellar medium could be more depleted in lithium in a lower galactic mass system due to it having a smaller reservoir of gas. We identified 93 GSE dwarf stars observed and analysed by the GALactic Archaeology with HERMES (GALAH) survey as part of its Data Release 3 (DR3). Orbital actions were used to select samples of GSE stars, and comparison samples of halo and disc stars. We find that the GSE stars show the same lithium abundance as other likely accreted stars and in situ Milky Way stars. Formation environment leaves no imprint on lithium abundances. This result fits within the growing consensus that the Spite plateau, and more generally the 'cosmological lithium problem' - the observed discrepancy between the amount of lithium in warm, metal-poor dwarf stars in our Galaxy, and the amount of lithium predicted to have been produced by big bang nucleosynthesis - is the result of lithium depletion processes within stars. |
Keywords | stars: abundances; Galaxy: evolution; Galaxy: halo; Astrophysics; Astrophysics of Galaxies |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2021 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Institution of Origin | University of Southern Queensland |
Byline Affiliations | University of New South Wales |
Macquarie University | |
National Institute for Astrophysics, Italy | |
University of Ljubljana, Slovenia | |
University of Sydney | |
Stockholm University, Sweden | |
Australian National University | |
Max Planck Society, Germany | |
Centre for Astrophysics | |
Johns Hopkins University, United States |
https://research.usq.edu.au/item/q6wqz/the-galah-survey-accreted-stars-also-inhabit-the-spite-plateau
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