  ZZ Ceti stars form the most numerous group of degenerate variable stars. They
are otherwise normal DA (H-rich atmospheres) white dwarfs that exhibit
pulsations. Here, we present an asteroseismological analysis for 44 bright ZZ
Ceti stars based on a new set of fully evolutionary DA white dwarf models
characterized by detailed chemical profiles from the centre to the surface. One
of our targets is the archetypal ZZ Ceti star G117$-$B15A, for which we obtain
an asteroseismological model with an effective temperature and a surface
gravity in excellent agreement with the spectroscopy. The asteroseismological
analysis of a set of 44 ZZ Ceti stars has the potential to characterize the
global properties of the class, in particular the thicknesses of the hydrogen
envelope and the stellar masses. Our results support the belief that white
dwarfs in the solar neighbourhood harbor a broad range of hydrogen-layer
thickness.
