Sökning: "white dwarfs"
Visar resultat 1 - 5 av 10 avhandlingar innehållade orden white dwarfs.
1. The faintest stars : A study of white, red and brown dwarfs
Sammanfattning : The local space density of the faintest stars, including M dwarfs, white dwarfs and brown dwarfs has been studied by two different methods.By using dark nebulae as opaque outer screens, the luminosity functions of M dwarfs and white dwarfs were studied as volume-limited and dynamically unbiassed foreground samples. LÄS MER
2. Inside Pulsating White Dwarfs: Clues from time-resolved spectroscopy
Sammanfattning : Several analyses using time-resolved optical spectrocopy of pulsating white dwarfs are presented. The data have been put to a number of uses. First, line-of-sight velocities associated with the pulsations have been measured in three hydrogen-atmosphere white dwarfs (DAVs), bringing the total number of such measurements up to five. LÄS MER
3. Stellar kinematics in surveys and simulations
Sammanfattning : 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. LÄS MER
4. Interacting Giants and Compact Stars
Sammanfattning : This thesis is based on four papers dealing with various aspects of interactions in binary stars. Interactions between stars occur at nearly all stages of their evolution and can take many forms. LÄS MER
5. Exotic phases of matter in compact stars
Sammanfattning : Astrophysical observations constitute an increasingly important source of information, thanks to the high resolution of present and near-future terrestrial and orbiting observatories. Especially, the properties of matter at low temperatures and extremely high densities can only be studied by observations of compact stellar objects. LÄS MER