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    Asteroseismology

    The recent research domain of asteroseismology refers to the study of the internal structure of pulsating stars through the interpretation of their frequency spectra. Asteroseismologists make great use of the oscillations to probe the stellar interior, which is not directly observable. The basic principles of asteroseismology are very much alike those developed by earth seismologists.

    No part of the Universe is more difficult to observe directly than the interior of the stars. The reason why stellar interiors can be probed from oscillations is that different oscillation modes penetrate to different depths inside the star. Asteroseismology is the only available method so far to derive the internal structure of the stars with high precision.

    Astrophysicists at the Institute of Astronomy of the University of Leuven play a central role in the interpretation of oscillation data of B-type stars. These are massive stars, with masses between 3 and 30 times the mass of the Sun. Stars heavier than roughly 9 solar masses will explode as a supernova at the end of their life. Thanks to such explosions, the interstellar medium is enriched with products of the nuclear burning in the stellar core, i.e. with chemical elements heavier than hydrogen and helium.

    Oscillations can be excited in stars when thermal energy is converted into kinetic energy of pulsation. Similarly as for any heat engine, this proces is effective if heat is absorbed in the high temperature phase of oscillation and emitted when the temperature is low. The main mechanism for stars is the net conversion of radiation energy into pulsational energy in the surface layers of some classes of stars. The resulting oscillations are usually studied under the assumption that they are small, and that the star is isolated and spherically symmetric. At the Institute of Astronomy, several basic properties of stellar oscillations have been developed and clarified, and we are interested in the behaviour of oscillating stars when the above assumptions are relaxed. In particular, we develop asymptotic representations of stellar oscillations, which are very useful for gaining insight into the deep layers of stars, and study the influence of stellar rotation and nonlinear effects on the oscillations. Furthermore, as multiple stars are very common, we investigate stellar tides and the effects of a tidal force on oscillating stars.

    For a more detailed basic text on asteroseismology of massive stars (including references), click here.

    To retrieve the discriminant code developed at the IvS to identify non-radial oscillation modes from line-profile variations, click here


      People involved
    Conny Aerts    Tim Van Hoolst    Paul Smeyers    Maryline Briquet    Fabien Carrier    Joris De Ridder    Katrien Kolenberg    Thierry Morel    Bart Vandenbussche    Jonas Debosscher    Karolien Lefever    Maarten Desmet    Maja Vuckovic    Rachel Drummond    Sophie Saesen   

      Related links
    Leuven Mercator telescope
    Networks:
    Belgian Asteroseismology Group
    Global Oscillation Network Group
    Whole Earth Telescope Project
    Delta Scuti Network
    Birmingham Solar Oscillations Network
    European Network of Excellence in AsteroSeismology (ENEAS)
    Space missions for asteroseismology:
    MOST webpage
    COROT webpage

K.U.Leuven - CWIS Copyright ©2011 Katholieke Universiteit Leuven | Comments on the content: Conny Aerts
Realisation: IvS system group | Last update: 06-04-2011
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