ATMOSPHERIC CHEMICAL-COMPOSITION OF AM STARS IN THE PLEIADES

Based on new spectroscopic observational data (high-resolution CCD spe ctrograms obtained with the coude spectrograph of the 2.6-m telescope) , we perform a model-atmosphere analysis of six A stars in the Pleiade s cluster which are classified as metallic-line stars. We determine th e atmospheric parameters of these stars and estimate their masses, rad ii, and luminosities from a comparison with evolutionary calculations. A comparison of the observed and synthetic spectra has yielded the at mospheric abundances of O, Si, Ca, Fe, and Ba in the stars. Using the currently available oscillator strengths, we determine the iron abunda nce in the atmospheres of the stars by the model-atmosphere method fro m published measurements of line equivalent widths. These results and the results of our previous abundance analysis of Coma stars lend supp ort to the conclusion that the differences in the atmospheric abundanc es of chemically peculiar stars in the same cluster are real.