Study of the Ultraviolet Spectra of Eta-Carinae

The IUE spectra of Eta Carinae were studied. The UV spectrum is characterized by strong resonance and intercombination lines with a very complex profile, and by a large amount of Fe II lines with P Cygni profile which are responsible for the very uneven UV energy distribution of the star. The IUE observations reveal high ionization species such as N V and He II not previously identified. This suggests the presence in the Eta Carinae wind of high temperature regions which could be associated to the X-ray emission found by the Einstein Satellite. The emission lines present a narrow peak overimposed on a broad, and frequently asymmetric emission, but the relative strength of the narrow and broad components differs from line to line, probably due to opacity effects and to deviations of the wind from the spherical symmetry. Low and high ionization lines coexist in regions of the wind with the same velocity. This suggests the presence of large inhomogeneities in the wind which could explain why in Eta Carinae there are effective mechanisms of dust condensation and of X-ray emission.