Ion signatures in supernova spectra

A systematic survey of ions that could be responsible for features in the o ptical spectra of supernovae is carried out. Six different compositions tha t could be encountered in supernovae are considered. For each composition, the LTE optical depth of one of the strongest optical lines of each ion is plotted against temperature. For each ion that can realistically be conside red as a candidate for producing identifiable features in supernova spectra , a sample synthetic spectrum is displayed. The optical depth plots and the synthetic spectra can provide guidance for studies of line identifications in the optical spectra of all types of supernovae during their photospheri c phases.