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Results 1 - 10
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4,877
Element Abundances in Nearby Galaxies
, 2002
"... In these lectures I present a highly opinionated review of the observed patterns of metallicity and element abundance ratios in nearby spiral, irregular, and dwarf elliptical galaxies, with connection to a number of astrophysical issues associated with chemical evolution. I also discuss some of the ..."
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In these lectures I present a highly opinionated review of the observed patterns of metallicity and element abundance ratios in nearby spiral, irregular, and dwarf elliptical galaxies, with connection to a number of astrophysical issues associated with chemical evolution. I also discuss some
Neutron-Capture Element Abundances and
, 2001
"... Abstract. Abundance ratios of radioactive to stable neutron-capture elements in very metal-poor stars may be used to estimate the age of our Galaxy. But extracting accurate ages from these data requires continuing work on many fronts: a) identification of more low metallicity stars with neutron-capt ..."
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Abstract. Abundance ratios of radioactive to stable neutron-capture elements in very metal-poor stars may be used to estimate the age of our Galaxy. But extracting accurate ages from these data requires continuing work on many fronts: a) identification of more low metallicity stars with neutron
Atmospheric parameters and element abundances
, 804
"... Received, accepted Context. The α Centauri binary system, owing to its duplicity, proximity and brightness, and its components ’ likeness to the Sun, is a fundamental calibrating object for the theory of stellar structure and evolution and the determination of stellar atmospheric parameters. This ro ..."
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. This role, however, is hindered by a considerable disagreement in the published analyses of its atmospheric parameters and abundances. Aims. We report a new spectroscopic analysis of both components of the α Centauri binary system, compare published analyses of the system, and attempt to quantify
Elemental Abundances in PG1159 Stars
, 710
"... Abstract. The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposing the usuallyhidden intershell region. Thus, the photospheric elemental abundance ..."
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abundances of these stars allow to draw conclusions about details of nuclear burning and mixing processes in the precursor AGB stars. We compare predicted elemental abundances to those determined by quantitative spectral analyses performed with advanced non-LTE model atmospheres. A good qualitative
Evolution of Elemental Abundances in Planetary Nebulae
, 2005
"... Abstract—We study the evolution of elemental abundances in an ensemble of Galactic planetary nebulae as a function of the masses of the central stars (Mcs) and their progenitors (Mini). We derive the dependences of the C, N, Ne, Cl, Ar, and S abundances on Mcs and Mini for a large sample of nebulae. ..."
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Abstract—We study the evolution of elemental abundances in an ensemble of Galactic planetary nebulae as a function of the masses of the central stars (Mcs) and their progenitors (Mini). We derive the dependences of the C, N, Ne, Cl, Ar, and S abundances on Mcs and Mini for a large sample of nebulae
Coronal and Solar Wind Elemental Abundances
"... Abstract. Coronal elemental abundances, as compared with abundances in the solar wind and solar energetic particles, provide the means for connecting solar wind gas with its coronal source. Comparison of coronal abundances with photospheric values shows fractionation with the ionization potential of ..."
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Abstract. Coronal elemental abundances, as compared with abundances in the solar wind and solar energetic particles, provide the means for connecting solar wind gas with its coronal source. Comparison of coronal abundances with photospheric values shows fractionation with the ionization potential
Element Abundances at High Redshifts 1
, 1999
"... Abstract. I review measurements of element abundances in different components of the high redshift universe, including the Lyman alpha forest, damped Lyman alpha systems, and Lyman break galaxies. Although progress is being made in all three areas, recent work has also produced some surprises and sh ..."
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Abstract. I review measurements of element abundances in different components of the high redshift universe, including the Lyman alpha forest, damped Lyman alpha systems, and Lyman break galaxies. Although progress is being made in all three areas, recent work has also produced some surprises
Results 1 - 10
of
4,877
