On the elemental abundance and isotopic mixture of mercury in HgMn stars

Optical region spectra of 31 HgMn stars have been studied for the abundance and isotope mixture of mercury. In the course of the investigation the lines Hg I lambda4358 and Hg II lambdalambda3984,6149 have been studied, with abundances established for all three lines in several HgMn stars. The mercury isotope mixture has been determined from high resolution spectra of the lambda3984 line. Possible signs of an ionization anomaly have been detected by the comparison of the abundance derived from the Hg I line and the Hg II lines in seven of the observed HgMn stars. A possible correlation of the mercury abundance with T-eff has been detected. Possible signs of a weak anticorrelation of the manganese and mercury abundance in HgMn stars have been found, which could be interpreted as a sign of inhomogeneous surface distribution of these elements. For a number of the HgMn stars in this study the mercury abundance and isotope mixture are reported for the first time.