Results 21 to 30 of about 9,431 (248)
Origin of Star-to-Star Abundance Inhomogeneities in Star Clusters [PDF]
Proceedings of the International Astronomical Union, 2008 AbstractThe mass reinserted by young stars of an emerging massive compact cluster shows a bimodal hydrodynamic behaviour. In the inner part of the cluster, it is thermally unstable, while in its outer parts it forms an out-blowing wind. The chemical homogeneity/inhomogeneity of low/high mass clusters demonstrates the relevance of this solution to the ...
Palouš, Jan +3 more
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Abundance Analysis of Planetary Host Stars. I. Differential Iron Abundances [PDF]
The Astronomical Journal, 2003 We present atmospheric parameters and iron abundances derived from high-resolution spectra for three samples of dwarf stars: stars which are known to host close-in giant planets (CGP), stars for which radial velocity data exclude the presence of a close-in giant planetary companion (no-CGP), as well as a random sample of dwarfs with a spectral type and
Heiter, U., Luck, R. E.
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Oxygen abundances in planet-harbouring stars [PDF]
Astronomy & Astrophysics, 2005 19 pages, 11 figures (low resolution), accepted for publication in A& ...
Ecuvillon, A. +5 more
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Sulphur abundance in Galactic stars [PDF]
Astronomy & Astrophysics, 2005 accepted by A& ...
Caffau, Elisabetta +5 more
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Chemical Abundances in Symbiotic Stars [PDF]
The Astrophysical Journal, 2008 We have carried out a study of the chemical abundances of $^1$H, $^4$He, $^{12}$C, $^{13}$C, $^{14}$N, $^{15}$N, $^{16}$O, $^{17}$O, $^{20}$Ne and $^{22}$Ne in symbiotic stars (SSs) by means of a population synthesis code. We find that the ratios of the number of O-rich SSs to that of C-rich SSs in our simulations are between 3.4 and 24.1, depending on
Lu, Guoliang +3 more
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Abundances in J-Type Carbon Stars [PDF]
International Astronomical Union Colloquium, 1988 It has been found by Utsumi(1985a,b) that in J-type carbon stars of C4-5 and WZ Cas(C9,2J Li), abundances of s-process elements with respect to Fe are nearly normal, while in normal carbon stars of C5-8, heavy metals are overabundant by factors of 10-100, and rare-earth elements are overabundant by a factor of about 10.In the MK system, most J-type ...
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Abundances in rapidly rotating a stars [PDF]
International Astronomical Union Colloquium, 1993 AbstractA study is undertaken to determine abundances in rapidly rotating main sequence A stars (v sin i = 100 − 180 km/s) in order to investigate if non-solar abundance patterns found in slow rotators (Lemke 1989, 1990) persist toward higher rotational velocities.
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Abundances in Wolf-Rayet Stars, LBVs and OBN Stars [PDF]
Symposium - International Astronomical Union, 1991 Current knowledge of the chemical nature of WR stars determined from UV, optical and IR spectral analyses, is reviewed. By number, the H/He ratio is low in most WN stars: 10 ≥ H/He ≥ 0.4 for WNL stars; 3.0 ≥ H/He ≥ 0.0 for WNE stars with most having near zero H-abundances.
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Surface abundances of ON stars [PDF]
Astronomy & Astrophysics, 2015 Massive stars burn hydrogen through the CNO cycle during most of their evolution. When mixing is efficient, or when mass transfer in binary systems happens, chemically processed material is observed at the surface of O and B stars. ON stars show stronger lines of nitrogen than morphologically normal counterparts.
Martins, F. +7 more
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Abundance analysis of barium stars [PDF]
Proceedings of the International Astronomical Union, 2013 AbstractWe obtained the chemical abundances of more than 20 Barium (Ba) stars by analysing high resolution echelle spectra. They show obvious overabundances of neutron capture process elements, such as Y, Zr, Ba, La and Eu. Their abundance pattern can be explained by binary accretion through stellar wind, where the Ba stars have accreted the ejecta ...
Guochao Yang +3 more
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