Bibcode
Weidner, C.; Koester, D.
Bibliographical reference
Astronomy and Astrophysics, v.406, p.657-666 (2003)
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8
2003
Journal
Citations
4
Refereed citations
3
Description
The numerical simulation method for variable white dwarfs of Ising &
Koester (2001) is extended to variable DB stars (DBVs or V777 Herculis
stars). We find the same general behavior of nonlinear effects, with a
sinusoidal light-curve at small amplitudes, strongly non-sinusoidal
variations at intermediate amplitudes and a change back to smaller and
sinusoidal variations at the largest driving pressure amplitudes. The
transition between the various regimes is however shifted to higher
amplitudes compared to DAVs because of the smoother reaction of the DB
convection zones to perturbations. A peculiar event of the prototype
GD358 - with all pulsation power going into one mode only - in August
1996 offers the possibility for a direct comparison of the light-curve
with our simulation. We can reproduce the light-curve, but only for
higher effective temperature than usually assumed. The wavelength
dependent amplitudes (chromatic amplitudes) of this object are not well
reproduced by our simulations, and various possible explanations are
discussed.