EDP Sciences
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Volume 399, Number 1, February III 2003
Page(s) 287 - 296
Section Formation and evolution of planetary systems
DOI http://dx.doi.org/10.1051/0004-6361:20021776

A&A 399, 287-296 (2003)
DOI: 10.1051/0004-6361:20021776

Line profile variability in the spectra of Oef stars

I. BD + 60 $^{\circ}$ 2522
G. Rauw, M. De Becker and J.-M. Vreux

Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août, Bât. B5c, 4000 Liège (Sart Tilman), Belgium
(Received 5 November 2002 / 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 $+60^{\circ}$ 2522. We find that the double-peaked He II $\lambda$ 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 $+60^{\circ}$ 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 $+60^{\circ}$ 2522 -- stars: variables: general

Offprint request: G. Rauw, rauw@astro.ulg.ac.be

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