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We present detailed chemical abundances for the bright carbon-enhancedmetal-poor (CEMP) star BD+44 493, previously reported on by Ito et al. Ourmeasurements 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 arefound for nitrogen and neutron-capture elements (the latter of which place itin the CEMP-no class of stars). Other elements that we measure exhibitabundance patterns that are typical for non-CEMP extremely metal-poor stars. Noevidence for variations of radial velocity have been found for this star. Theseresults strongly suggest that the carbon enhancement in BD+44 493 is unlikelyto have been produced by a companion asymptotic giant-branch star andtransferred to the presently observed star, nor by pollution of its natalmolecular cloud by rapidly-rotating, massive, mega metal-poor ([Fe/H] < -6.0)stars. A more likely possibility is that this star formed from gas polluted bythe elements produced in a "faint" supernova, which underwent mixing andfallback, and only ejected small amounts of elements of metals beyond thelighter elements. The Li abundance of BD+44 493 (A(Li)=log(Li/H)+12=1.0) islower than the Spite plateau value, as found in other metal-poor subgiants. Theupper limit on Be abundance (A(Be)=log(Be/H)+12<-1.8) is as low as those foundfor stars with similarly extremely-low metallicity, indicating that theprogenitors of carbon- (and oxygen-) enhanced stars are not significant sourcesof Be, or that Be is depleted in metal-poor subgiants with effectivetemperatures of ~5400K.

Chemical Analysis of the Ninth Magnitude Carbon-Enhanced Metal-Poor Star BD+44 493