Results 311 to 320 of about 64,475 (321)
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Nucleosynthesis and future stellar abundance determinations
EAS Publications Series, 2004AbstractFor Abstract see ChemInform Abstract in Full Text.
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Element Abundances in Stellar Coronae
1996About two years ago, the intrigue of the solar “FIP Effect”—that coronal abundances of elements with a low FIP (≲ 10 eV; e.g Fe, Mg, Si, Ca) are observed to be enhanced relative to those of high FIP elements (≳ 10 eV; e.g. O, Ne, S; see e.g. the review by Meyer 1993)—prompted us to study stellar coronal abundances based on new EUV spectra obtained with
J. J. Drake, J. M. Laming, K. G. Widing
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Stellar chemical abundances with the GHRS
Physica Scripta, 1996The accurate quantitative analysis of high resolution ultraviolet spectra of ultra-sharp-lined early-type, chemically peculiar stars, obtained with the Goddard High Resolution spectrograph on the Hubble Space Telescope, has been made possible by the synergism between state-of-the-art astro-physics and state-of-the-art atomic spectroscopy. We illustrate
David S Leckrone +4 more
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Abundance measurements in stellar environments
AIP Conference Proceedings, 2014Most of what we know about stars, and systems of stars, is derived from the analysis of their electromagnetic radiation. This lesson is an attempt to describe to Physicists, without any Astrophysical background, the framework to understand the present status of abundance determination in stellar environments and its limit.
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From Stellar Spectra to Abundances
Astrophysics and Space Science, 2001The current techniques of stellar abundances determination from high resolution spectra are discussed, and the related uncertainties arising from the analysis are examined. These involve the observational uncertainties but also physical data, and atmosphere models accuracy. This critical assessment is then used to shed light on the controversial [O/Fe]
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Abundance ratios in quasi-stellar objects
Astrophysics and Space Science, 1977Relative abundances of carbon and aluminium with respect to silicon have been calculated in the QSOs PHL957, PKS0237-23, 1331+170, 3C191 and M132. Relative abundance of Fe with respect to Mg has been also calculated in the QSOs 1331+170 and PHL938. The ratiosN(C)/N(Si),N(Al)/N(Si) andN(Fe)/N(Mg) in QSOs considered as a class are (5.5±1.6), (0.13±0.03 ...
R. K. Thakur, P. K. Mishra
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Stellar nucleosynthesis and galactic abundances
AIP Conference Proceedings, 2001Galactic abundances are neither constant in time nor do they evolve in a simple fashion, e.g., by an enrichment of heavy elements in constant relative proportions. Instead, their evolution in space and time reflects the history of star formation and the lifetimes of the diverse contributing stellar objects.
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Elemental abundances for stellars-process studies
Astrophysics and Space Science, 1987Nuclear reaction network calculations of heavy element enhancements are tabulated for different values of the mean neutron exposure τ0. These tables are useful for comparison with observeds-process abundance patterns which appear to span a wide range in τ0.
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Stellar Abundances — First Generation to Solar
AIP Conference Proceedings, 2006The discovery and analysis of metal‐poor stars lead to insight into conditions when the Universe and Galaxy were young. We present the rationale for studying such objects (which become progressively rarer at lowest abundance), with a description of their systematic discovery, culminating in the recent analysis of two objects having [Fe/H] < −5.0.
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