Sökning: "abundances"
Visar resultat 6 - 10 av 181 avhandlingar innehållade ordet abundances.
6. Stochastic Chemical Evolution : A Study of Scatter in Relative Elemental Abundances in Extremely Metal-poor Stars
Sammanfattning : 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. LÄS MER
7. On the Abundances of Li, Be and O in Metal-Poor Stars in the Galaxy
Sammanfattning : 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. LÄS MER
8. The nature of stars with a common origin: clues from metallicity, elemental abundances, and kinematics
Sammanfattning : Most of field stars originate from dissolved star clusters. If the gas cloud is well mixed the stars in the cluster are expected to be chemically homogenous. LÄS MER
9. A study of possible chemical inhomogeneities of dwarf irregular galaxies and the influence on the Z-L relationship
Sammanfattning : A study on the chemical abundances of dwarf irregular galaxies (dI's) is presented in this work. This type of galaxies have typically low metallicity. First of all, a definition of dI is proposed, in order to obtain a homogeneous group of targets. LÄS MER
10. On the Chemical Composition of Metal-Poor Stars : Impact of Stellar Granulation and Departures from Local Thermodynamic Equilibrium on the Formation of Spectral Lines
Sammanfattning : 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. LÄS MER
