Model Extreme Ultraviolet Spectra of Highly Ionized Iron

We present synthetic spectra of the extreme ultraviolet emission of highly ionized Iron (Fe XVI through Fe XXIV). The Iron model is part of a larger effort to revise the Raymond & Smith code (Ap.J. Suppl. 35, 1977, p.419) and to update the atomic rates. As such, comparisons of our predicted spectra with existing theoretical models, observed solar spectra, and the recent EUVE spectrum of Capella (cf A. Dupree et al./, this BAAS) provide important tests of the new atomic data. We have incorporated into our model the new Iron ionization equilibria of Arnaud and Raymond (Ap.J. 398, 1992, p.394), with significant effects in the higher temperature regime from new dielectronic recombination rates. Furthermore, we have compiled new collisional excitation rates, some with accuracies around 10%. Detailed comparisons of predicted and observed Iron spectral lines are discussed. This work was performed under NASA Grant NAGW-528 to Smithsonian Astrophysical Observatory.