INTERMEDIATE AND HEAVY LANTHANIDES IN THE SILICON STAR HD 192913, AND THE PROBLEM OF THE LANTHANIDE ABUNDANCE DISTRIBUTIONS IN PECULIAR A STARS

The spectra of several intermediate and heavy lanthanides, including Ho IIi, and Er III have been positively identified in the spectrum of the silicon star HD 192913. Both the identification of these ions and their occurrence in a silicon star are unusual. These results are discussed in terms of an empirical two-component model of the distribution of lanthanide abundances in Ap stars.