Precise determination of stellar parameters of the ZZ Ceti and DAZ white dwarf GD 133 through asteroseismology

An increasing number of white dwarfstars show atmospheric chemical composition polluted by heavy elements accreted from debris diskmaterial. The existence of such debris disksstrongly suggests the presence of one or more planet(s) whose gravitational interaction with rocky planetesimalsis responsible for their disruption by tidal effect. The ZZ Ceti pulsator and polluted DAZ white dwarfGD 133 is a good candidate for searching for such a potential planet. We started in 2011 a photometric follow-up of its pulsations. As a result of this work in progress, we used the data gathered from 2011 to 2015 to make an asteroseismologicalanalysis of GD 133, providing the star parameters from a best fit modelwith $M$/$M_{\odot}$ = 0.630 $\pm$ 0.002, $T_{\rm eff}$ = 12400 K $\pm$ 70 K, log($M_{\rm He}/M$) = -2.00 $\pm$ 0.02, log($M_{\rm H}/M$) = -4.50 $\pm$ 0.02 and determining a rotation periodof $\approx$ 7 days.