Carbon-Enhanced Metal-Poor Stars in the Early Galaxy

التفاصيل البيبلوغرافية
العنوان: Carbon-Enhanced Metal-Poor Stars in the Early Galaxy
المؤلفون: B. Marsteller, Silvia Rossi, Norbert Christlieb, Michael S. Bessell, Timothy C. Beers, J. Rhee
المصدر: Nuclear Physics A. 758:312-315
بيانات النشر: Elsevier BV, 2005.
سنة النشر: 2005
مصطلحات موضوعية: Physics, Nuclear and High Energy Physics, Initial mass function, Metallicity, K-type main-sequence star, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy, Astrophysics, Galaxy, Abundance of the chemical elements, Radial velocity, Stars, Stellar evolution
الوصف: Very metal-deficient stars that exhibit enhancements of their carbon abundances are of crucial importance for understanding a number of issues -- the nature of stellar evolution among the first generations of stars, the shape of the Initial Mass Function, and the relationship between carbon enhancement and neutron-capture processes, in particular the astrophysical s-process. One recent discovery from objective-prism surveys dedicated to the discovery of metal-deficient stars is that the frequency of Carbon-Enhanced Metal-Poor (CEMP) stars increases with declining metallicity, reaching roughly 25% for [Fe/H] < -2.5. In order to explore this phenomenon in greater detail we have obtained medium-resolution (2 A) spectroscopy for about 350 of the 413 objects in the Christlieb et al. catalog of carbon-rich stars, selected from the Hamburg/ESO objective prism survey on the basis of their carbon-enhancement, rather than metal deficiency. Based on these spectra, and near-IR JHK photometry from the 2MASS Point Source Catalog, we obtain estimates of [Fe/H] and [C/Fe] for most of the stars in this sample, along with reasonably accurate determinations of their radial velocities. Of particular importance, we find that the upper envelope of carbon enhancement observed for these stars is nearly constant, at [C/H] ~ -1.0, over the metallicity range -4.0 < [Fe/H] < -2.0; this same level of [C/H] applies to the most iron-deficent star yet discovered, HE 0107-5240, at [Fe/H] = -5.3.
Contributed paper to The Eigth Nuclei in the Cosmos conference, to appear (in refereed form) in Nuclear Physics A
تدمد: 0375-9474
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::64e1794d90535138753a2717313b2545
https://doi.org/10.1016/j.nuclphysa.2005.05.056
حقوق: OPEN
رقم الأكسشن: edsair.doi.dedup.....64e1794d90535138753a2717313b2545
قاعدة البيانات: OpenAIRE