SIMBAD references

Using high-time-resolution ultraviolet spectroscopy, we present evidence that variability in the stellar wind of the O7.5 III(n)((f)) star ξ Per takes place essentially over the whole velocity range over which the wind is observable in absorption: from ~-100 km/s in the SiIV line up to -2750 km/s in NV and CIV, about 400 km/s beyond the terminal velocity of the stellar wind. The variations in the absorption part of the P Cygni profile include the discrete absorption components (DACs), which represent the strongest manifestations of the wind variability. In contrast, the emission part of the profile is steady. The blue steep edge in the saturated P Cygni lines varies in concert with the DACs. The changes in the subordinate NIV line at 1718A at low velocity (~-250 to ~-800 km/s) are found to vary in concert with the appearance of DACs in the SiIV lines. This implies that DACs are formed in a region relatively close to the surface. An evaluation of the statistical significance of variations in IUE spectra is presented.