The spectral variability of HD 192639 and its implications for the star's wind structure
English
Rauw, Grégor[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE) - Sciences spatiales >]
Morrison, N. D.[Ritter Astrophysical Research Center, Toledo, OH 43606, USA]
Vreux, Jean-Marie[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > > ]
Gosset, Eric[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE) >]
Mulliss, C. L.[Ritter Astrophysical Research Center, Toledo, OH 43606, USA]
[en] LINE: PROFILES ; STARS: EARLY-TYPE ; STARS: MASS LOSS ; STARS: INDIVIDUAL: HD 192639 ; STARS: VARIABLES: GENERAL
[en] We report the analysis of an extensive set of spectroscopic data of the O(f) supergiant HD 192639. A Fourier analysis of our time-series reveals a recurrent variability with a ``period'' of roughly 4.8 days which is most prominent in the absorption components of the He {ii}\ lambda 4686 and Halpha P-Cygni profiles. The same periodicity is also detected in the blue wing of several absorption lines (e.g. Hbeta ). The variations of the absorption components correspond most probably to a cyclical modulation of the amount of stellar wind material along the line of sight towards the star. The 4.8-day period affects also the morphology of the double-peaked He {ii}\ lambda 4686 and Halpha emission components, although these emission components display also variations on other (mainly longer) time scales. The most likely explanation for the 4.8-day modulation is that this cycle reflects the stellar rotational period (or half this period). We find that the most important observational properties can be explained - at least qualitatively - by a corotating interaction region or a tilted confined corotating wind. Based on observations collected at the Observatoire de Haute Provence, France and the Ritter Observatory, Toledo, USA.
[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE) - Sciences spatiales >]
