CONICET | Buscador de Institutos y Recursos Humanos

In recent years, the increasing evidence that a signicant fraction of white dwarfs is accreting matterfrom a debris disk has triggered a signicant scientic interest. Its mere existence suggests that the planetary systemwhich had formed around the star was able to survive all previous phases of stellar evolution, including thoseimplying dramatic size changes as well as mass loss events of the central star. The computation of accretion ratesprovides us important information about the original planetary system. Unfortunately the present estimations donot take into account a physical process that may happen when heavy material falls ontop a lighter one, generatingturbulences that dilutes the accreted material. This process aects directly the computed accretion rates, sinceif it takes place, larger accretion rates become necessary in order to explain the amount of surface contaminationobserved. In this work we present the results of numerical simulations that show that this destabilizing physicalprocess actually occurs. Its impact on an accreting DA white dwarf model is presented.