Chemical analysis of the ninth magnitude carbon-enhanced metal-poor star BD+44°493

Abstract

We present detailed chemical abundances for the bright carbon-enhanced metal-poor (CEMP) star BD+44°493, previously reported on by Ito et al. Our measurements confirm that BD+44°493 is an extremely metal-poor ([Fe/H] =-3.8) subgiant star with excesses of carbon and oxygen. No significant excesses are found for nitrogen and neutron-capture elements (the latter of which place it in the CEMP-no class of stars). Other elements that we measure exhibit abundance patterns that are typical for non-CEMP extremely metal-poor stars. No evidence for variations of radial velocity has been found for this star. These results strongly suggest that the carbon enhancement in BD+44°493 is unlikely to have been produced by a companion asymptotic giant-branch star and transferred to the presently observed star, nor by pollution of its natal molecular cloud by rapidly-rotating, massive, mega metal-poor ([Fe/H]