QUASI-MOLECULAR SATELLITES OF LYMAN-BETA IN ORFEUS OBSERVATIONS OF DAWHITE-DWARFS

Quasi-molecular satellite features of Ly beta were first observed in a HUT spectrum of the DA white dwarf Wolf 1346 and interpreted by Koest er et al. (1996). In this paper we study the dependence of these featu res on temperature and surface gravity in 4 additional DA observed wit h ORFEUS-SPAS II in 1996. For the interpretation we use theoretical at mosphere models which incorporate new profiles for Ly beta. These have been calculated by Allard et al. (1998a) including the variation of t he transition probability with distance between emitter and perturber. The new calculations for the general line shape, satellite positions and strengths are in very good agreement with the observations.