Hot-Am stars as intermediary objects to the HgMn and Am stars

Abstract

We describe the early results of an investigation into the spectral characteristics of the hottest Am stars (A0 - A2) in an attempt to link the HgMn and Am classes of chemical peculiarity. A limited sample of hot-Am stars was searched for the presence of lines from the very heavy elements platinum and mercury, as well as a search for lines from the rare-earth elements in HgMn stars. Our analysis of the strong optical platinum and mercury lines in the spectrum of the HgMn star HR 7775 has detected isotopic shifts that are different from those found at ultraviolet wavelengths and, in the case of mercury, vary with ionization stage.