Journal article
The GALAH survey: verifying abundance trends in the open cluster M67 using non-LTE modelling
Monthly notices of the Royal Astronomical Society, Vol.481(2), pp.2666-2684
12/01/2018
DOI: 10.1093/mnras/sty2414
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 O.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.
Details
- Title: Subtitle
- The GALAH survey: verifying abundance trends in the open cluster M67 using non-LTE modelling
- Creators
- Xudong Gao - Heidelberg UniversityKarin Lind - Uppsala UniversityAnish M. Amarsi - Max Planck Institute for AstronomySven Buder - Heidelberg UniversityAaron Dotter - Center for Astrophysics Harvard & SmithsonianThomas Nordlander - ARC Centre of Excellence for All-sky AstrophysicsMartin Asplund - Mount Stromlo ObservatoryJoss Bland-Hawthorn - ASTRO-3DGayandhi M. De Silva - Australian Astronomical ObservatoryValentina D'Orazi - Osserv Astron Padova, Ist Nazl Astrofis, Vicolo Osservatorio 5, I-35122 Padua, ItalyKen C. Freeman - Mount Stromlo ObservatoryJanez Kos - University of SydneyGeraint F. Lewis - University of SydneyJane Lin - Australian National UniversitySarah L. Martell - UNSW SydneyKatharine J. Schlesinger - Australian National UniversitySanjib Sharma - University of SydneyJeffrey D. Simpson - UNSW SydneyDaniel B. Zucker - Macquarie UniversityTomaz Zwitter - University of LjubljanaGary Da Costa - Mount Stromlo ObservatoryBorja Anguiano - University of VirginiaJonathan Horner - University of Southern QueenslandElaina A. Hyde - Western Sydney UniversityPrajwal R. Kafle - International Centre for Radio Astronomy ResearchDavid M. Nataf - Johns Hopkins UniversityWarren Reid - Macquarie UniversityDennis Stello - Macquarie UniversityYuan-Sen Ting - Princeton UniversityGALAH Collaboration
- Resource Type
- Journal article
- Publication Details
- Monthly notices of the Royal Astronomical Society, Vol.481(2), pp.2666-2684
- Publisher
- Oxford Univ Press
- DOI
- 10.1093/mnras/sty2414
- ISSN
- 0035-8711
- eISSN
- 1365-2966
- Number of pages
- 19
- Grant note
- CE170100013 / Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D); Australian Research Council DE140100598 / Australian Research Council GRANTS:15529661; DE140100598 / Australian Research Council Alexander von Humboldt Foundation P1-0188 / Slovenian Research Agency; Slovenian Research Agency - Slovenia INCA 600398 / Marie Sklodowska Curie Actions; Marie Curie Actions 2015-004153 / Swedish Research Council
- Language
- English
- Date published
- 12/01/2018
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984701830902771
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