Narrow components in UV line profiles as evidence for a two component stellar wind for 0 and B stars

Abstract

The UV resonance lines of early type stars show narrow absorption components, with a width of the order of 300 km s-1, superimposed on the wider P Cygni profiles. Such narrow components have been detected in the Copernicus spectra of a few early type stars by Morton (1976) and Snow and Morton (1979). The variability of these components was studied by Snow (1977) who compared two scans of the UV line profiles of 15 stars taken about four years apart. He found that the narrow components do not change in velocity (except for the CIII λ 1175 line in ζ, Pup) but that the strength of the components can change drastically. In some stars the narrow components were present in only one of the two spectra. We studied the characteristics of these narrow components in the Copernicus spectra (Snow and Jenkins, 1977). The stars are listed in Table 1. Examples of these narrow components are shown in Figure 1.