The Spectrum of Pt II in Chemically Peculiar Stars

A reliable estimate of the platinum abundance in HgMn stars has been obtained for the first time. It is as high as log A(Pt) = 6, on the scale log A(H) = 12; the Pt abundance often matches the remarkably high abundances of Hg already known in these stars. The results are based on calculations of theoretical oscillator strengths which were applied to high resolution spectra taken with the International Ultraviolet Explorer satellite. The method of spectrum synthesis has been used to obtain the abundances. Astrophysical absolute oscillator strengths for the optical Pt II lines are derived based on the spectrum of the star Chi Lupi.