Abundances of elements in the atmospheres of sharp-lined Hg–Mn stars

The abundances of 14 elements in the atmospheres of 20 sharp-lined Hg–Mn stars were derived from published equivalent widths and microdensitometer tracings of high-resolution spectra covering the wavelength range from 3900 to 4650 Å. The Hg–Mn stars were compared with the normal A0 IV star γ Gem by the differential curve-of-growth method. Numerous weak lines were used in the analysis. There are large excesses of P, Sc, Mn, Ga, Sr, Y, Zr, Pt and Hg in some stars, but Mg and Ni are generally deficient and Sc and V are deficient in the cooler stars. No correlation of the abundances with the periodic table was found. Although there are large variations in the relative abundances of elements even among stars with similar effective temperatures, overall trends with effective temperature may exist for P, Sc, Mn and Pt. The excesses of Pt in the seven coolest stars are large and remarkably similar, but the isotopic composition of Pt and Hg varies from star to star. Both diffusion and accretion mechanisms may be necessary to account for all the abundance patterns and anomalies.