ATOMIC DATA FOR NON-LTE MODEL STELLAR ATMOSPHERES

We briefly review the state-of-the-art in non-LTE modeling of hot star atmospheres. During the last decade, the development. of a new class of radiation transfer methods, based an the Accelerated Lambda Iterati on method have brought considerable progress in this field. Severe lim itations of the size of model atoms used in non-LTE model atmospheres have been removed, so that realistic model atoms can now be considered . In recent years, the problem of non-LTE line blanketing, which aims to include the influence of thousands to millions of lines on the atmo spheric structure, has been attacked, and first non-LTE line-blanketed models have been calculated. We illustrate the importance of non-LTE line blanketing with the example of a hot subdwarf, BD + 75 degrees 32 5. As a consequence of these developments, there is a need for extensi ve radiative and collisional atomic databases to build non-LTE models. Recent projects, like the Opacity Project, provide a substantial quan tity of the necessary data. We discuss the current needs of atomic dat a for the purpose of building reliable non-LTE line-blanketed model at mospheres. A critical evaluation of the quality of such extensive sets of atomic data is essential. Finally, we present a new, IDL-based, gr aphic tool intended to facilitate the manipulation of large amounts of data needed to build the realistic model atoms that we use.