Chemical analysis of the metal-poor subgiant BD+44 493

DOI

We present detailed chemical abundances for the bright carbon-enhanced metal-poor (CEMP) star BD+44{deg}493, previously reported on by Ito et al. (2009ApJ...698L..37I). Our measurements confirm that BD+44{deg}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{deg}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]<-6.0) stars. A more likely possibility is that this star formed from gas polluted by the elements produced in a "faint" supernova, which underwent mixing and fallback, and only ejected small amounts of elements of metals beyond the lighter elements. The Li abundance of BD+44{deg}493 (A(Li)=log(Li/H)+12=1.0) is lower than the Spite plateau value, as found in other metal-poor subgiants. The upper limit on Be abundance (A(Be)=log(Be/H)+12<-1.8) is as low as those found for stars with similarly extremely-low metallicity, indicating that the progenitors of carbon- (and oxygen-) enhanced stars are not significant sources of Be, or that Be is depleted in metal-poor subgiants with effective temperatures of ~5400K.

Identifier
DOI http://doi.org/10.26093/cds/vizier.17730033
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/773/33
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/773/33
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/773/33
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/773/33
Provenance
Creator Ito H.; Aoki W.; Beers T.C.; Tominaga N.; Honda S.; Carollo D.
Publisher CDS
Publication Year 2015
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy