On the ultraviolet spectrum of Nova Cygni 1978.
Clavel, J.; Macchetto, F.; Cassatella, A.; Heck, A.; Benvenuti, P.; Selvelli, P. L.; Penston, M.
Spain, Netherlands
Abstract
Ultraviolet high- and low-resolution spectra of Nova Cygni 1978 have been obtained with IUE at three dates during the first month after its outburst (Sept. 13). The high-resolution spectrum of Sept. 28 is dominated, in the range 2300-2800 A, by broad undisplaced emission lines of singly ionized metals like Fe II, Cr II, and Mn II. The widths of these lines indicate expansion velocities of about 310 km/sec. Larger expansion velocities are observed in some O III fluorescence lines. A P Cygni profile is observed in the Mg II doublet lines. Most of the same spectral features are found in the earlier spectrum of Sept. 14-15. The low-resolution spectrum obtained on Oct. 10 indicates higher degrees of excitation and ionization than the earlier spectra.