The ultraviolet spectrum of the old novae HR Del, GK Per, RR Pic, andRS Oph.

Abstract

Spectroscopic observations of three old novae and a recurrent nova, all of them at minimum, have been carried out with the IUE satellite. The two slow novae HR Del and RR Pic have similar spectroscopic characters with absorption and emission features of high ionization over a continuum which does not follow a unique power law but seems to be formed by the contribution of a very hot component at short wavelengths and a lower temperature component at long wavelengths. Some differences in the spectra of the two stars are pointed out.