An inquiry into the nature of spectra from hot astrophysical plasma abnormally enriched with mercury

Observatories such as Chandra, XMM-Newton, and more likely future instruments with higher effective collecting area of radiation will offer the opportunity to study the nature of chemically peculiar sources using observations in the X-ray and EUV range. In the present work we explore the possibility to observe the spectral signature of highly stripped Hg ions that might be present in possible coronae or winds of HgMn stars. A systematic theoretical survey of the most intense X-ray spectral features predicted to be emitted by H-like to Pd-like Hg ions (Hg+79 Hg+34) is performed. The calculated intensities ( photons s(-1) ion(-1)) of the various spectral features of the Hg ions are compared to the intensities calculated for the lines of Fe ions that may be observed in the same range of the X-ray spectrum, but not necessarily from the same temperature domain. Fe lines corresponding to transitions from the L electronic shell were already observed in the coronae of stars, e.g., by Chandra in Capella. Assuming a similar abundance for Hg and Fe ions, many of the calculated Hg lines are found to be of comparable intensity to the Fe lines and in some cases stronger by about a factor of 20. We also discuss possible density and temperature diagnostic applications for some of the Hg lines.