To be published in:
Astronomy & Astrophysics
Line profile variability in the spectra of Oef stars:
I. BD+60° 2522+
M. De Becker1 and
1 Institut d'Astrophysique et de Géophysique - Université de Liège, Allée du 6 Août, Bât B5c, B-4000 Liège (Sart Tilman), Belgium
* Research Associate FNRS, Belgium
+ Based on observations collected at the Observatoire de Haute Provence, France.
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 HeII
4686 emission line undergoes strong
profile variability on time scales of 2 - 3 days. 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 days time scale variability.
Line: profiles -- stars: early-type -- stars: mass loss --
stars: individual: BD+60° 2522 -- stars: variables: other