Search for dissertations about: "Stellar abundances"
Showing result 1 - 5 of 34 swedish dissertations containing the words Stellar abundances.
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1. On the Abundances of Li, Be and O in Metal-Poor Stars in the Galaxy
Abstract : Stellar atmospheres constitute excellent environments to study the chemical evolution of our Galaxy. The chemical composition of these atmospheres reflects the composition of the gas from where these stars were born. READ MORE
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2. Atomic Processes in Stellar Atmospheres : Inelastic Collisions and Effects on Late-type Spectra
Abstract : Chemical abundances as measured from stellar spectral lines are often subject to uncertainties due to lack of accurate data for inelastic collisions, which is needed for non-local thermodynamic equilibrium (non-LTE) modelling. For cool stars, understanding of collision processes with electrons and hydrogen atoms is required to achieve high precision measurements. READ MORE
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3. On the Chemical Composition of Metal-Poor Stars : Impact of Stellar Granulation and Departures from Local Thermodynamic Equilibrium on the Formation of Spectral Lines
Abstract : The information about the chemical compositions of stars is encoded in their spectra. Accurate determinations of these compositions are crucial for our understanding of stellar nucleosynthesis and Galactic chemical evolution. READ MORE
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4. Theoretical Atomic Spectroscopy of Earthbound and Stellar Plasma
Abstract : Motivated by spectroscopic analysis of astrophysical and laboratory plasma, this thesis concerns the fundamental structure and spectral properties of atoms and their ions. The multiconfiguration Dirac-Hartree-Fock (MCDHF) method is used to predict the emission or absorption of radiation, by atomic systems in general, and of heavy and highly charged ions in particular. READ MORE
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5. Dwarf and Subgiant Stars as Probes of Galactic Chemical and Dynamical Evolution
Abstract : Stellar chemical abundances provide astronomers with vital information about the production of chemical elements. Some stars preserve the composition of the environment in which they were born on their surfaces. READ MORE