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The GALAH survey: co-orbiting stars and chemical tagging.

Authors :
Simpson, Jeffrey D
Martell, Sarah L
Da Costa, Gary
Casey, Andrew R
Freeman, Ken C
Horner, Jonathan
Ting, Yuan-Sen
Nataf, David M
Lewis, Geraint F
Ness, Melissa K
Zucker, Daniel B
Cottrell, Peter L
Čotar, Klemen
Asplund, Martin
Bland-Hawthorn, Joss
Buder, Sven
D'Orazi, Valentina
De Silva, Gayandhi M
Duong, Ly
Kos, Janez
Source :
Monthly Notices of the Royal Astronomical Society; Feb2019, Vol. 482 Issue 4, p5302-5315, 14p
Publication Year :
2019

Abstract

We present a study using the second data release of the GALAH survey of stellar parameters and elemental abundances of 15 pairs of stars identified by Oh et al. They identified these pairs as potentially co-moving pairs using proper motions and parallaxes from Gaia DR1. We find that 11 very wide (>1 pc) pairs of stars do in fact have similar Galactic orbits, while a further four claimed co-moving pairs are not truly co-orbiting. Eight of the 11 co-orbiting pairs have reliable stellar parameters and abundances, and we find that three of those are quite similar in their abundance patterns, while five have significant [Fe/H] differences. For the latter, this indicates that they could be co-orbiting because of the general dynamical coldness of the thin disc, or perhaps resonances induced by the Galaxy, rather than a shared formation site. Stars such as these, wide binaries, debris of past star formation episodes, and coincidental co-orbiters, are crucial for exploring the limits of chemical tagging in the Milky Way. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00358711
Volume :
482
Issue :
4
Database :
Complementary Index
Journal :
Monthly Notices of the Royal Astronomical Society
Publication Type :
Academic Journal
Accession number :
133666020
Full Text :
https://doi.org/10.1093/mnras/sty3042