Abstract
With its unprecedented sensitivity and spectral resolution, FUSE has been a source of important data that have helped us further our knowledge and understanding of white dwarf stars. In order to illustrate the crucial contribution of FUSE to the study of white dwarfs, we present an abundance analysis of Si based on FUSE observations of 83 hydrogen-rich (DA) white dwarfs. Studying the Si abundances in the atmospheres of white dwarfs is important for understanding the mechanisms that counteract the downward diffusion of elements heavier than hydrogen. The FUSE observations show that Si is present in about 25% of white dwarfs. The Si abundances show a large scatter that is difficult to interpret in terms of a strict equilibrium between the gravitation and the radiative levitation. © 2009 American Institute of Physics.