Carbon-rich RR Lyr type stars

Abstract

We have derived CNO abundances in 12 RR Lyrae stars. Four stars show [C/Fe] near 0.0 and two stars show [C/Fe] = 0.52 and 0.65. Red giant branch stars, which are known to be the predecessors of RR Lyrae stars, generally show a deficiency of carbon due to proton captures during their evolution from the main sequence up the giant branch. We suggest that the enhancement of carbon is due to production during the helium flash combined with mixing to the surface by vigorous convection induced by the flash itself.

accepted for publication in ApJL

References in corpus (5)

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Cited by in corpus (9)

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• On the Use of Field RR Lyrae as Galactic Probes. II. A new $\Delta$S calibration to estimate their metallicity
• The chemical composition of carbon stars: The R-type stars
• Study of Globular Cluster M53: new variables, distance, metallicity
• The Pristine survey II: a sample of bright stars observed with FEROS
• Seven New Carbon-Enhanced Metal-Poor RR Lyrae Stars
• A New CEMP-s RR Lyrae Star
• Multi-wavelength Photometric Study of RR Lyrae Variables in the Globular Cluster NGC 5272 (Messier 3)
• NLTE CNO abundances in a sample of nine field RR lyr type stars