Radial velocity and profile variations of the ultraviolet circumstellar lines in ζ tauri

Abstract

The radial velocity and profile variations of UV lines of the shell star ζ Tau have been examined in the IUE spectra obtained in 1978–1982. The neutral atoms, and once or twice-ionized ions (exceptCII, AlIII, SiIII resonance lines) follow the same velocity variations as in the visual spectra, while the SiIV andCIV resonance lines show a constant negative velocity (∼‑50 km s^‑1 at the core). The AlIII,CII resonance lines and probably FeIII (mult. No. 34) are formed in both regions, i.e., in lowly-ionized and highly-ionized regions and the SiIII resonance line is formed in a highly-ionized region.