The GALAH survey: a catalogue of carbon-enhanced stars and CEMP candidates. Issue 3 (22nd November 2018)

• Record Type: Journal Article
• Authors: Čotar, Klemen; Zwitter, Tomaž; Kos, Janez; Munari, Ulisse; Martell, Sarah L; Asplund, Martin; Bland-Hawthorn, Joss; Buder, Sven; De Silva, Gayandhi M; Freeman, Kenneth C; Sharma, Sanjib; Anguiano, Borja; Carollo, Daniela; Horner, Jonathan; Lewis, Geraint F; Nataf, David M; Nordlander, Thomas; Stello, Denis; Ting, Yuan-Sen; Tinney, Chris; Traven, Gregor; Wittenmyer, Rob A; the GALAH collaboration,
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 483:Issue 3(2019)
• Page Start: 3196
• Page End: 3212
• Publication Date: 2018-11-22
• Subjects: methods: data analysis -- catalogues -- stars: abundances -- stars: carbon; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/sty3155
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Swan bands – characteristic molecular absorption features of the C2 molecule – are a spectroscopic signature of carbon-enhanced stars. They can also be used to identify carbon-enhanced metal-poor (CEMP) stars. The GALAH (GALactic Archaeology with Hermes) is a magnitude-limited survey of stars producing high-resolution, high-signal-to-noise spectra. We used 627 708 GALAH spectra to search for carbon-enhanced stars with a supervised and unsupervised classification algorithm, relying on the imprint of the Swan bands. We identified 918 carbon-enhanced stars, including 12 already described in the literature. An unbiased selection function of the GALAH survey allows us to perform a population study of carbon-enhanced stars. Most of them are giants, out of which we find 28 CEMP candidates. A large fraction of our carbon-enhanced stars with repeated observations show variation in radial velocity, hinting that there is a large fraction of variables among them. 32 of the detected stars also show strong Lithium enhancement in their spectra.