P14	February 1998

¹ Institut d'Astrophysique et de Géophysique - Université de Liège, Avenue de Cointe 5, 4000 Liège, Belgium

⁺ Based on observations collected at the Observatoire de Haute Provence, France.

Abstract

     We report the results of a medium-resolution spectroscopic investigation of the O(f) supergiant HD 192639. Particular attention is paid to the He II 4686 line. This line displays strong profile variability on time scales of a few days, changing from a P-Cygni profile with a double-peaked emission component to a pure blue-shifted emission line. It appears that the variability of most of the absorption lines present in our spectra is correlated to the deformation of the He II 4686 line and arises probably from a large scale structure in the low-velocity part of the stellar wind rather than from a photospheric phenomenon. We find that the time scale of the variability could be consistent with the estimated rotational period of HD 192639.