EDP Sciences
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Volume 406, Number 1, July IV 2003
Page(s) 281 - 285
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20030747

A&A 406, 281-285 (2003)
DOI: 10.1051/0004-6361:20030747

Surface imaging of stellar non-radial pulsations

II. The $\mathsf{\beta}$ Cephei star $\mathsf{\omega^{1}}$ Sco
S. V. Berdyugina1, 2, J. H. Telting3, H. Korhonen1, 4 and C. Schrijvers5

1  Astronomy Division, University of Oulu, PO Box 3000, 90401 Oulu, Finland
2  Institute of Astronomy, ETHZ, 8092 Zurich, Switzerland
3  Nordic Optical Telescope, Apartado 474, 38700 S/C de La Palma, Canarias, Spain
4  Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
5  Astronomical Institute Anton Pannekoek, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands

(Received 10 February 2003 / Accepted 13 May 2003 )

We apply the surface imaging technique to high-resolution spectra of the rapidly rotating $\beta$ Cep-type star $\omega^{1}$ Sco which shows strong line-profile variations in the $\ion{Si}{iii}$ $\lambda$ 4552, 4567, 4574 Å triplet. These variations have been interpreted in terms of non-radial pulsations by Telting & Schrijvers (1998). Their analysis of the spectral time series with traditional Fourier transforms resulted in one significant frequency, suggesting that the profile variations are due to only one dominant pulsation mode. Here we apply a spectral inversion technique to the same time series of the profiles. Assuming only temperature fluctuations due to pulsations, we obtain an image of the dominant pulsation mode. We estimate the pulsation degree from the image, put constraints on the azimuthal number of the mode, and study the latitudinal distribution of the pulsation pattern. In addition to the known dominant mode we find traces of a second pulsation mode.

Key words: stars: oscillations -- stars: imaging -- stars: early-type -- stars: individual: $\omega^{1}$ Sco

Offprint request: S. V. Berdyugina, sveta@astro.phys.ethz.ch

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