
arXiv: 1807.07977
Swan bands - characteristic molecular absorption features of the C$_2$ 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.
13+5 pages, 13 figures, 1 catalog, accepted to MNRAS
astrophysics, stars: abundances, solar and stellar astrophysics, Stars: abundances, FOS: Physical sciences, Catalogues, methods: data analysis, Astrophysics - Astrophysics of Galaxies, 520, stars: carbon, Stars: carbon, Astrophysics - Solar and Stellar Astrophysics, Methods: data analysis, Astrophysics of Galaxies (astro-ph.GA), galaxies, catalogues, Solar and Stellar Astrophysics (astro-ph.SR)
astrophysics, stars: abundances, solar and stellar astrophysics, Stars: abundances, FOS: Physical sciences, Catalogues, methods: data analysis, Astrophysics - Astrophysics of Galaxies, 520, stars: carbon, Stars: carbon, Astrophysics - Solar and Stellar Astrophysics, Methods: data analysis, Astrophysics of Galaxies (astro-ph.GA), galaxies, catalogues, Solar and Stellar Astrophysics (astro-ph.SR)
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