Preprint Logo P78 August
2002


To be published in:
Astronomy & Astrophysics

Line profile variability in the spectra of Oef stars:
I. BD+60° 2522+

G. Rauw1,*, M. De Becker1 and J.-M. Vreux1


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.


Abstract

     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.

Key Words
Line: profiles -- stars: early-type -- stars: mass loss -- stars: individual: BD+60° 2522 -- stars: variables: other

Files
Article: bd60.ps.gz (209612 bytes): HTTP FTP (ftp://vela.astro.ulg.ac.be/preprints/)


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