Abstract
A progress report on the analysis of the IUE high-resolution, far-UV spectra of a sample of 29 O4-B0 and sdO stars is presented. Some morphological properties of the N V wavelength 1238-1242 lines are mentioned and, from a comparison with the C IV wavelength 1548-1551 profiles, the possibility of different CNO abundance effects in the stellar sample is explored. For the stars in the sample, the HD and BD numbers, the spectral types, the IUE image number, the OB association to which the star probably belongs, and the maximum expansion velocity at which N V and C IV can be detected are listed. It is suggested that the possible effects of CNO chemical abundance variations may explain differences in these maximum wavelength displacements. The CNO relative abundance differences would be due to evolutionary effects that tend to increase the nitrogen abundance with time.
