IUE observations of interstellar SI IV and C IV lines observed in thespectra of Wolf-Rayet stars.

Abstract

Recent IUE observations of Wolf-Rayet stars show narrow absorption lines in the highly ionized species of Si IV and C IV. These are observed in the spectra of 10 WR stars which are being studied as part of an extensive investigation of this stellar class with the IUE satellite. The strengths of the sharp Si IV and C IV undisplaced absorption lines observed in these spectra are discussed. It is concluded that these lines arise not in the general interstellar medium, but in H II regions associated with the stars themselves with, in some cases, additional contributions from the hot gas related to active interstellar regions. The interstellar spectrum of one star, HD 50896, is briefly discussed. Violet shifted absorptions in the interstellar lines of low ionization species are observed in the spectra of this star, which are believed to arise in the ring nebula S308 surrounding the star. This represents the second observation of absorption lines arising in a ring nebula surrounding a WR star.