Sökning: "stellar populations"

Visar resultat 6 - 10 av 20 avhandlingar innehållade orden stellar populations.

  1. 6. The cosmic origin of fluorine and sulphur: Infrared spectroscopic studies of red giants

    Författare :Henrik Jönsson; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemical evolution; near-infrared and mid-infrared spectroscopy; stellar abundances;

    Sammanfattning : Disregarding the small primordial traces of the lightest elements, all metals have been formed in stellar processes, which means that the relative amount of metals in the Universe increases for every stellar generation. This build-up of elements is called chemical evolution and might be used both to constrain stellar models as well as understanding the formation and evolution of stellar populations. LÄS MER

  3. 7. Star clusters as engines of galaxy evolution

    Författare :Mattia Sirressi; Angela Adamo; Matthew Hayes; Paul Crowther; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Extragalactic astronomy; Galaxies; Star formation; Interstellar medium; Stellar feedback; Ultraviolet surveys; Hubble Space Telescope; Spectroscopy; Data analysis; Astronomy; astronomi;

    Sammanfattning : Feedback in star forming galaxies is the key process that regulates how many stars form given the available gas reservoir. The radiation, energy and momentum released by the stellar activity and the active galactic nuclei change the physical properties of the gas in the galaxy such as the ionisation state, the density and the kinematics. LÄS MER

  4. 8. Quasars and Low Surface Brightness Galaxies as Probes of Dark Matter

    Författare :Erik Zackrisson; Nils Bergvall; Kjell Olofsson; Julianne Dalcanton; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Cosmology: dark matter; gravitational lensing; quasars: general; quasars: redshift; galaxies: halos; galaxies: formation; galaxies: stellar content; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik;

    Sammanfattning : Most of the matter in the Universe appears to be in some form which does not emit or absorb light. While evidence for the existence of this dark matter has accumulated over the last seventy years, its nature remains elusive. LÄS MER

  5. 9. Exploring the Chemical Evolution of Globular Clusters and their Stars : Observational Constraints on Atomic Diffusion and Cluster Pollution in NGC 6752 and M4

    Författare :Pieter Gruyters; Andreas Korn; Piercarlo Bonifacio; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: abundances – stars: atmospheres – stars: fundamental parameters – globular clusters: individual: NGC 6752 and M4 – techniques: spectroscopic; Astronomy with specialization in Astrophysics; Astronomi med intiktning mot astrofysik;

    Sammanfattning : Through the cosmic matter cycle, the chemical evolution of the Milky Way is imprinted in the elemental abundance patterns of late-type stars (spectral types F to K). Due to their long lifetimes ( 1 Hubble time), these stars are of particular importance when it comes to studying the build-up of elements during the early times of our Galaxy. LÄS MER

  7. 10. The origin and chemical evolution of iron-peak and neutron-capture elements in the Milky Way disk

    Författare :Chiara Battistini; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Stars: abundances; Stars: solar-type; Galaxy: disk; Galaxy: evolution; Galaxy: solar neighbourhood;

    Sammanfattning : All the elements heavier than Li are created during stellar evolution. Even if our knowledge of this process is good, many questions still remain. LÄS MER