Observations of narrow absorption components in the ultraviolet spectrum of zeta Ophiuchi.

Abstract

Narrow absorption components due to the resonance transitions of C IV and N V are noted to be present in all 33 high resolution IUE spectra of Zeta Ophiuchi obtained between 1978 and 1981, though Doppler shifted by -1385 km/sec. An examination of previous observations shows these features to have been present for at least 12 years, and it is determined that significant changes in the narrow components accompanied an H-alpha emission episode. The column densities of the material responsible for the narrow components and for the underlying P Cygni profiles are estimated by means of profile fitting, leading to a discussion of these results in the context of possible models for the formation of the narrow components. It is concluded that none of the currently available models is entirely capable of accounting for observations.