Search for dissertations about: "STELLAR"
Showing result 1 - 5 of 159 swedish dissertations containing the word STELLAR.
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1. Stellar Winds of Cool Giants : Investigating the Mass-Loss Mechanism of AGB Stars
Abstract : Asymptotic giant branch (AGB) stars are luminous cool giants of low to intermediate mass that are strongly pulsating and non-spherical, with heavy mass loss through a stellar wind. The mass loss makes these stars important for galactic chemistry, as the wind enriches the interstellar medium with new elements and dust, and it determines the final fate of these stars. READ MORE
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2. Stellar kinematics in surveys and simulations
Abstract : We study stellar motions in the Milky Way with N-body simulations and large astrometric samples from ESA's Gaia mission. We identify two kinematic populations for white dwarfs in the Solar neighbourhood. We also investigate the accreted halo and reveal two new structures. READ MORE
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3. Characterising Young Stellar Binaries
Abstract : Stars are dispersed all over the sky within our Galaxy, appearing in large varieties of ages and sizes. How- ever, estimating said traits proves not to always be trivial, but certain circumstances allow us to probe the characteristics of stellar binaries. READ MORE
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4. 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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5. 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