Sökning: "Metallicity"
Visar resultat 1 - 5 av 43 uppsatser innehållade ordet Metallicity.
1. Measuring copper abundances in the Galactic Bulge
Kandidat-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionenSammanfattning : Context: The chemical evolution of Cu in the Galactic bulge have been studied in a few studies using red giant branch stars, but the ages of individual red giant stars are difficult to determine. In addition, the bulge has been a challenging region of the Milky Way galaxy to obtain high-resolution spectra of stars, except when observing through certain few small fields into the bulge that are known to have low extinction. LÄS MER
2. Potassium in the Galactic Bulge - as traced by microlensed dwarf & sub-giant stars
Kandidat-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionenSammanfattning : During this report the potassium (K) trend in the Galactic Bulge, with respect to metallicity and various α-elements, has been computed and evaluated by a method of line synthesis on the 7698.96 ̊A KI line (7699 KI), where Non-Local-Thermal-Equilibrium (NLTE) effects have been considered. LÄS MER
3. What limits the luminosity of red supergiants?
Kandidat-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionenSammanfattning : The observed upper limit of the luminosity of red supergiants, often called the Humphreys-Davidson limit, has recently been shown to be independent of metallicity and to not be explainable by single star evolution – findings that both contradict established ideas of the origins of the limit. It is now known that the vast majority of stars with sufficient mass to possibly evolve into red supergiants above the limit interact with companion stars at some point during their lives. LÄS MER
4. Can Dwarf Galaxies Tell Us How the Milky Way Formed?
Master-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionenSammanfattning : Dwarf galaxies are a key component in understanding the evolution of galaxies and provide tests on the standard cosmological $\Lambda$ Cold Dark Matter model. According to the formation hierarchy, dwarf galaxies are the pieces that create all galaxies. Our current understanding of dwarf galaxies faces discrepancies between theory and observations. LÄS MER
5. Forming wide-orbit planets via pebble accretion
Master-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionenSammanfattning : The possibility that detected substructures in protoplanetary disks, such as gaps, rings and cavities, are created by distant protoplanets has prompted an inquiry into the mechanism responsible for their formation. These wide-orbit young bodies are likely to form relatively rapidly in the outer regions of circumstellar disks. LÄS MER
