Search for dissertations about: "white dwarfs"

Showing result 1 - 5 of 10 swedish dissertations containing the words white dwarfs.

  2. 1. The faintest stars : A study of white, red and brown dwarfs

    Author : Leif Festin; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; brown dwarfs; white dwarfs; M dwarf; low luminosity; luminosity function; mass function; Pleiades; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; astronomi; Astronomy;

    Abstract : 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. READ MORE

  4. 2. Inside Pulsating White Dwarfs: Clues from time-resolved spectroscopy

    Author : Rubina Kotak; Astronomi - Genomgår omorganisation; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; pulsating white dwarfs; convection; asteroseismology; Astronomi; Astronomy; spectroscopy; Fysicumarkivet A:2002:Kotak;

    Abstract : 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. READ MORE

  5. 3. Stellar kinematics in surveys and simulations

    Author : Daniel Mikkola; Astronomi - Genomgår omorganisation; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Galactic dynamics; stellar dynamics; simulations; Gaia; Galactic dynamics; Stellar kinematics; Numerical simulations; Statistical methods; Solar neighborhood;

    Abstract : 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. READ MORE

  6. 4. Interacting Giants and Compact Stars

    Author : Alexey Bobrick; Astronomi - Genomgår omorganisation; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; stars Binaries: General; stars : neutron; stars : subdwarfs; stars : supergiants; hydrodynamics; nuclear reactions; nucleosynthesis; abundances; stars Binaries: General; stars : neutron; stars : subdwarfs; stars : supergiants; hydrodynamics; nuclear reactions; nucleosynthesis; abundances; Fysicumarkivet A:2021:Bobrick;

    Abstract : 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. READ MORE

  7. 5. Exotic phases of matter in compact stars

    Author : Fredrik Sandin; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Fysik; Fysik;

    Abstract : 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. READ MORE