Wavelength shift and probable isotopic structure of Pt II lambda 4046 in mercury stars.

Measurements on coude' spectrograms of nine Hg-Pt stars show that Pt ii A4046 is shifted toward longer wavelength by 0.04 to 0.09 A from the centroid for terrestrial platinum. High-resolution scans made with a Fabry-Perot interferometer show a single exceedingly sharp component in x Lup A, which probably represents a single heavy isotope. In CrB two or more heavy isotopes appear to be present. Subject headings: abundances, stellar - peculiar A stars