LINE BLANKETING BY IRON-GROUP ELEMENTS IN NON-LTE MODEL ATMOSPHERES FOR HOT STARS

We present the first metal line blanketed non-LTE model atmospheres fo r O stars which include 130 000 lines of the iron group elements scand ium through nickel, a subset from Kurucz' (1991) line list, fully self -consistently. It is shown that even the treatment of the complete lin e list (> 10(6) lines) in NLTE models poses no longer any fundamental problem. The numerical solution of the metal line blanketing problem c onsists of an opacity sampling technique within the framework of the A ccelerated Lambda Iteration method. Exploratory models with different parameters were successfully constructed, e.g. for hot subdwarfs and c entral stars of planetary nebulae as well as for white dwarfs. We disc uss the blanketing effects of metal lines (i) onto the atmospheric str atification, (ii) onto UV and EUV fluxes, (iii) onto the emergent H an d He line profiles, and (iv) the potential of iron lines as sensitive temperature indicators. The models are used to interprete EUV observat ions of the white dwarf G191-B2B and UV spectra of the hot sdO star BD +28-degrees 4211.