Line profile variability in the spectra of Oef stars*
I. BD + 60° 2522
Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août, Bât. B5c, 4000 Liège (Sart Tilman), Belgium
Corresponding author: G. Rauw, email@example.com
Accepted: 14 November 2002
We report the analysis of a long term observing campaign designed to monitor the spectroscopic variability of the Oef star BD +60° 2522. We find that the double-peaked He ii λ 4686 emission line undergoes strong profile variability on time scales of 2–3 day. However, the time scale as well as the pattern of these variations turn out to be epoch dependent and the phenomenon is thus most likely not ruled by a single stable clock. On the other hand, the absorption lines in the spectrum of BD +60° 2522 display line profile variability on time scales of a few hours that might be related to non-radial pulsations. We tentatively propose that the beating of several non-radial pulsation modes triggers transient large-scale density perturbations in a confined stellar wind that produce the 2–3 day time scale variability.
Key words: line: profiles / stars: early-type / stars: mass-loss / stars: individual: BD +60° 2522 / stars: variables: general
© ESO, 2003