Search for dissertations about: "metal-poor stars"

Showing result 1 - 5 of 15 swedish dissertations containing the words metal-poor stars.

  2. 1. Galactic archaeology with metal-poor stars

    Author : Thomas Nordlander; Andreas J. Korn; Karin Lind; Ulrike Heiter; David L. Lambert; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; stars: abundances; radiative transfer; stars: Population II; stars: Population III;

    Abstract : The chemical fingerprints of old, metal-poor stars can be used to unravel the events of the newborn Universe and help us understand the properties of the first stars and star clusters. The study of nearby stars to infer properties in the distant past is often referred to as Galactic archaeology. READ MORE

  4. 2. On the Chemical Composition of Metal-Poor Stars : Impact of Stellar Granulation and Departures from Local Thermodynamic Equilibrium on the Formation of Spectral Lines

    Author : Remo Collet; Bengt Gustafsson; Martin Asplund; Roger Cayrel; Uppsala universitet; []
    Keywords : Astronomy; late-type stars; stellar abundances; stellar atmospheres; spectral line formation; convection; hydrodynamics; Galactic chemical evolution; Astronomi;

    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

  5. 3. Stochastic Chemical Evolution : A Study of Scatter in Relative Elemental Abundances in Extremely Metal-poor Stars

    Author : Torgny Karlsson; Bengt Gustafsson; Mike Edmunds; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; nucleosynthesis; chemical evolution; Galactic evolution; supernovae; chemical abundances; Population II stars; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik;

    Abstract : Chemical evolution addresses the problem of the formation of the chemical elements and their evolution throughout the history of the universe. This thesis discusses in particular the chemical evolution in the young universe and what we may learn from the observations of the oldest stars. READ MORE

  6. 4. Measurements of High-Precision Atomic Data with Applications to Astrophysics and Cosmology

    Author : Maria Aldenius; Astronomi - Genomgår omorganisation; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; atomic data; Ca; Cr; Fe; Mn; Mg; metal-poor stars; fine-structure constant; Fourier transform spectroscopy; nebulae; oscillator strengths; spectroscopy; wavelengths; Ti; Zn; Astronomy; Astronomi; Atomic and molecular physics; Atom- och molekylärfysik; rymdvetenskap; space research; cosmic chemistry; kosmisk kemi; branching fractions;

    Abstract : Investigations of astrophysical spectra require accurate atomic data, such as wavelengths and transition probabilities. This thesis provides high-precision atomic data for astrophysical and cosmological applications. The measurements have been carried out using Fourier transform spectrometry on light produced in a hollow cathode light source. READ MORE

  7. 5. On the Abundances of Li, Be and O in Metal-Poor Stars in the Galaxy

    Author : Ana Elia García Pérez; Martin Asplund; Bengt Gustafsson; Francesca Primas; Beatriz Barbuy; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; galactic evolution; stellar abundances; stellar atmospheres; spectral line formation; stellar mixing; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik;

    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