High-Resolution IUE Spectra of the Nova-like Variable IX Velorum

Abstract

The paper addresses two separate but related studies utilizing high-resolution ultraviolet spectra of the nova-like variable IX Velorum, obtained by the IUE satellite. The observations used in the studies are described, and the velocity offsets of the broad Si IV absorption features and the variability of the shapes of the P Cygni profiles of Si IV and C IV on the orbital period are analyzed. Given the results of these studies, the implications for the wind in which these profiles are formed are assessed. It is noted that the component of the wind in which Si IV dominates lies at a lower velocity and originates in a smaller volume than the component of the wind in which C IV dominates. The narrow spectral features in the P Cygni profiles of Si IV and C IV are analyzed, possible explanations for their formation are considered, and their properties are compared with those of early-type stars.