Bibcode
Weidner, C.; Koester, D.
Referencia bibliográfica
Astronomische Gesellschaft Abstract Series, Vol. 18. Abstracts of Contributed Talks and Posters presented at the Annual Scientific Meeting of the Astronomische Gesellschaft at the Joint European and National Meeting JENAM 2001 of the European Astronomical Society and the Astronomische Gesellschaft at Munich, September 10-15, 2001, abstract #P113.
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2001
Número de citas
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Número de citas referidas
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Descripción
Asteroseismology is a very powerful technique to study the interior of
pulsating stars like the ZZ Ceti white dwarfs (DAV), because the driving
mechanism is strongly correlated with the chemical composition of the
layers in the star. The necessary first step is the identification of
the pulsation mode. In contrast to our sun most DA variables (H-rich
atmospheres) have only few pulsation modes, making standard
mode-identification techniques difficult or even impossible. In order to
understand the exact nature of the mode excitation and to improve the
identification Brickhill (1983) did semi-analytical calculations and Wu
(1998) & Wu (2001) performed a pertubation analysis of the mode
driving zones and the layers above. However, numerical simulations of
light curves (Ising & Koester, 2001) did not confirm all results.
The most important difference is that even for the fundamental mode the
surface distribution of the flux amplitudes is different from the
spherical harmonics of the pulsation mode in deeper layers. As a
consequence normalized amplitude spectra depend not only on the mode
number l but also on pulsation amplitude and inclination. Following the
work of J. Ising on DAV the main goal of this research is to extend the
range of effective temperatures and chemical compositions. Futhermore
the effects of non-linearity and multiple pulsation frequencies on
mode-identification are studied, aiming towards the comparison with
observations.