The GALAH survey: a catalogue of carbon-enhanced stars and CEMP candidates

K. Cotar, T Zwitter, Janez Kos, U Munari, Sarah Martell, Martin Asplund, Joss Bland-Hawthorn, Sven Buder, Gayandhi M De Silva, Kenneth Freeman, Sanjib Sharma, Borja Anguiano, David M Nataf, Thomas Nordlander, Dennis Stello, Yuan-Sen Ting

    Research output: Contribution to journalArticlepeer-review

    9 Citations (Scopus)

    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.
    Original languageEnglish
    Pages (from-to)3196-3212
    JournalMonthly Notices of the Royal Astronomical Society
    Volume483
    Issue number3
    DOIs
    Publication statusPublished - 2019

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