منابع مشابه
New beryllium observations in low-metallicity stars
We present observations of the Be II 313.0 nm resonance doublet in 14 halo and old disk stars with metallicities ranging from [Fe/H]=-0.4 to≈-3.0 obtained with the CASPEC spectrograph of the ESO 3.6m telescope at a FWHM≈ 8.6 kms−1 resolution. Abundances are derived bymeans of the synthetic spectra technique employing Kurucz (1993) atmospheric models, with enhanced α-elements and no overshooting...
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Nobuyuki IWAMOTO1,∗, Toshitaka KAJINO, Grant J. MATHEWS, Masayuki Y. FUJIMOTO and Wako AOKI National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan The Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556, USA Department of Physics, Hokkaido Univ...
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Mass loss plays a dominant role in the evolution of massive stars at solar metallicity. After discussing different mass loss mechanisms and their metallicity dependence, we present the possibility of strong mass loss at very low metallicity. Our models at Z = 10−8 show that stars more massive than about 60 M⊙ may lose a significant fraction of their initial mass in the red supergiant phase. Thi...
متن کاملThe Lowest Metallicity Stars from SDSS/SEGUE
The first extension of the Sloan Digital Sky Survey (SDSS-II), which included the program SEGUE: Sloan Extension for Galactic Understanding and Exploration, ended in July, 2008. This effort, in which JINA was an institutional partner, has already produced the largest sample of medium-resolution stellar spectra yet obtained. These data are revolutionizing our understanding of the nature of the s...
متن کاملLow Metallicity Stars in Our Galaxy
The advent of 8 m class telescopes has allowed the detailed spectroscopic study of sizeable numbers of extremely metal-poor Galactic stars which are the witnesses of the formation of the early Galaxy. Their chemical composition displays some distinctive trends which should provide a strong constraint on the physical nature of the first generation(s) of stars and on their nucleosynthetic output....
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2014
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/201322440