EDP Sciences
Free access
Volume 404, Number 2, June III 2003
Page(s) L29 - L32
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20030574

A&A 404, L29-L32 (2003)
DOI: 10.1051/0004-6361:20030574


New type of brightness variations of the colliding wind WO4 + O5((f)) binary WR 30a

S. J. Paardekooper1, K. A. van der Hucht2, A. M. van Genderen1, E. Brogt3, M. Gieles4 and R. Meijerink1

1  Leiden Observatory, Postbus 9513, 2300 RA Leiden, The Netherlands
2  SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
3  University of Groningen, Kapteyn Astronomical Institute, PO Box 800, 9700 AV, Groningen, The Netherlands
4  Astronomical Institute, PO Box 80000, 3508 TA Utrecht, The Netherlands

(Received 13 March 2003 / Accepted 16 April 2003)

We present new photometric observations in Johnson V and B of WR 30a, revealing relative dramatic changes in brightness of $0\fm 2$. These variations occur on a time scale of hours, and are only seen in V. We argue that they are not caused by dust extinction, but either by a dramatic change in the strength of the C IV 5801-12 Å emission line doublet due to a de-excitation process, or by some unknown continuum effect.

Key words: stars: binaries -- stars: Wolf-Rayet -- stars: individual: WR 30a

Offprint request: K. A. van der Hucht, K.A.van.der.Hucht@sron.nl

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