The GALAH survey: verifying abundance trends in the open cluster M67 using non-LTE modelling
Article
Article Title | The GALAH survey: verifying abundance trends in the open cluster M67 using non-LTE modelling |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Gao, Xudong (Author), Lind, Karin (Author), Amarsi, Anish M. (Author), Buder, Sven (Author), Dotter, Aaron (Author), Nordlander, Thomas (Author), Asplund, Martin (Author), Bland-Hawthorn, Joss (Author), de Silva, Gayandhi M. (Author), D'Orazi, Valentina (Author), Freeman, Ken C. (Author), Kos, Janez (Author), Lewis, Geraint F. (Author), Lin, Jane (Author), Martell, Sarah L. (Author), Schlesinger, Katharine J. (Author), Sharma, Sanjib (Author), Simpson, Jeffrey D. (Author), Zucker, Daniel B. (Author), Zwitter, Tomaz (Author), Da Costa, Gary (Author), Anguiano, Borja (Author), Horner, Jonathan (Author), Hyde, Elaina A. (Author), Kafle, Prajwal R. (Author), Nataf, David M. (Author), Reid, Warren (Author), Stello, Dennis (Author) and Ting, Yuan-Sen (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 481 (2), pp. 2666-2684 |
Number of Pages | 19 |
Year | 2018 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/sty2414 |
Web Address (URL) | https://academic.oup.com/mnras/article/481/2/2666/5090981 |
Abstract | Open cluster members are coeval and share the same initial bulk chemical composition. Consequently, differences in surface abundances between members of a cluster that are at different evolutionary stages can be used to study the effects of mixing and internal chemical processing. We carry out an abundance analysis of seven elements (Li, O, Na, Mg, Al, Si, and Fe) in 66 stars belonging to the open cluster M67, based on high resolution GALAH spectra, 1D MARCS model atmospheres, and non-local thermodynamic equilibrium (non-LTE) radiative transfer. From the non-LTE analysis, we find a typical star-to-star scatter in the abundance ratios of around 0.05 dex. We find trends in the abundance ratios with effective temperature, indicating systematic differences in the surface abundances between turn-off and giant stars; these trends are more pronounced when LTE is assumed. However, trends with effective temperature remain significant for Al and Si also in non-LTE. Finally, we compare the derived abundances with prediction from stellar evolution models including effects of atomic diffusion. We find overall good agreement for the abundance patterns of dwarfs and sub-giant stars, but the abundances of cool giants are lower relative to less evolved stars than predicted by the diffusion models, in particular for Mg. |
Keywords | radiative transfer; stars; abundances; atmospheres; late-type; astrophysics; stellar astrophysics |
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 ©: 2018 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 | Max Planck Society, Germany |
Center for Astrophysics Harvard and Smithsonian, United States | |
Australian National University | |
University of Sydney | |
Australian Astronomical Observatory, Australia | |
National Institute for Astrophysics, Italy | |
University of New South Wales | |
Macquarie University | |
University of Ljubljana, Slovenia | |
University of Virginia, United States | |
School of Agricultural, Computational and Environmental Sciences | |
Western Sydney University | |
University of Western Australia | |
Johns Hopkins University, United States | |
University of Western Sydney | |
Macquarie University | |
Institute for Advanced Study, United States |
https://research.usq.edu.au/item/q5188/the-galah-survey-verifying-abundance-trends-in-the-open-cluster-m67-using-non-lte-modelling
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