SPECTROSCOPIC STUDIES OF DB-WHITE-DWARFS - CONFIRMATION AND MODELING OF NEW FORBIDDEN COMPONENTS OF HE-I

Red optical spectrophotometry of three DB white dwarfs confirms the ex istence, first reported by Greenstein and Liebert, of new forbidden co mponents of He I transitions near 6068 and 6632 Angstrom in the spectr a of these stars. However, our search for the additional components te ntatively reported earlier near 5379, 6337, and 6485 Angstrom remained unsuccessful. New model atmosphere calculations are presented which s trengthen the identification of the confirmed features as, respectivel y, the forbidden 2 P-3-3 P-3 and 2 P-1-3 P-1 transitions in the He I i on, which arise from Stark perturbations of the upper atomic levels. O ur calculations show, furthermore, that these features, which should b e generally present in the red spectra of hot DB stars, are predicted with a strength comparable to that observed.