Estimation of Carbon Abundances in Metal-Poor Stars. I. Application to the "Strong G-band" stars of Beers, Preston, & Shectman

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dc.creatorRossi, Silvia
dc.creatorBeers, Timothy C.
dc.creatorSneden, Chris
dc.creatorSevastyanenko, Tatiana
dc.creatorRhee, Jaehyon
dc.creatorMarsteller, Brian
dc.date2005-08-09
dc.date.accessioned2026-07-07T11:24:40Z
dc.date.available2026-07-07T11:24:40Z
dc.descriptionWe develop and test a method for the estimation of metallicities ([Fe/H]) and carbon abundance ratios ([C/Fe]) for carbon-enhanced metal-poor (CEMP) stars, based on application of artificial neural networks, regressions, and synthesis models to medium-resolution (1-2 A) spectra and J-K colors. We calibrate this method by comparison with metallicities and carbon abundance determinations for 118 stars with available high-resolution analyses reported in the recent literature. The neural network and regression approaches make use of a previously defined set of line-strength indices quantifying the strength of the CaII K line and the CH G-band, in conjuction with J-K colors from the 2MASS Point Source Catalog. The use of near-IR colors, as opposed to broadband B-V colors, is required because of the potentially large affect of strong molecular carbon bands on bluer color indices. Using these methods we are able to reproduce the previously-measured [Fe/H] and [C/Fe] determinations with an accuracy of ~ 0.25 dex for stars in the metallicity interval -5.5 <= [Fe/H]} <= -1.0, and with 0.2 <= (J-K)o <= 0.8. At higher metallicity the CaII K line begins to saturate, especially for the cool stars in our program, hence this approach is not useful in some cases. As a first application, we estimate the abundances of [Fe/H] and [C/Fe] for the 56 stars identified as possibly carbon-rich, relative to stars of similar metal abundance, in the sample of "strong G-band" stars discussed by Beers, Preston, & Shectman. (abridged)
dc.description51 pages, including 12 figures and 7 tables, accepted for publication in the Astronomical Journal
dc.identifierhttps://arxiv.org/abs/astro-ph/0508202
dc.identifierhttp://arxiv.org/abs/astro-ph/0508202
dc.identifierAstron.J.130:2804-2823,2005
dc.identifierdoi:10.1086/497164
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/195267
dc.subjectAstrophysics
dc.titleEstimation of Carbon Abundances in Metal-Poor Stars. I. Application to the "Strong G-band" stars of Beers, Preston, & Shectman
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