Issue |
A&A
Volume 409, Number 1, October I 2003
|
|
---|---|---|
Page(s) | 275 - 286 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20031086 | |
Published online | 17 November 2003 |
Rotation and magnetic field in the Be star ω Orionis*,**
1
GEPI/UMR 8111 du CNRS, Observatoire de Paris-Meudon, France
2
Sterrenkundig Instituut “Anton Pannekoek”, Universiteit van Amsterdam, The Netherlands
3
RSSD, ESTEC / ESA, Keplerlaan 1, 2201 AZ Noordwijk ZH, The Netherlands
4
Département d'Astrophysique de l'Université de Nice-Sophia Antipolis, UMR 6525 du CNRS, France
5
Astronomical Observatory Beograd, MNTRS 1940, Volgina 7, 11050 Beograd, Serbia
6
Max Plank Institut für Aeronomie, Lindau, Germany
7
Institut d'Astrophysique de Paris (IAP), France
Corresponding author: C. Neiner, cneiner@rssd.esa.int
Received:
21
March
2003
Accepted:
7
July
2003
ω Ori is a B2IIIe star for which rotational modulation and
non-radial pulsations (NRP) have been recently investigated from two independent
observational campaigns in 1998 and 1999. Putting the data of these 2 campaigns
together, and adding data obtained in 2001, we search for multiperiodicity in
the line profile variations and evidence for outbursts. From new spectropolarimetric data
obtained at the Télescope Bernard Lyot (TBL, Pic du Midi, France) in 2001
we also measure the Stokes V parameter in the polarised
light. We find evidence for the presence of a weak magnetic field in
ω Ori sinusoidally varying with a period of 1.29 d. The
equivalent widths (EW) of the wind sensitive UV resonance lines also show a
variation with the same period, which we identify as the rotational period of the
star. We propose an oblique rotator model and derive G to
explain the observations. Moreover, we carry out an abundance analysis
and find the star to be N-enriched, a property which is shared with other
magnetic stars. We propose ω Ori as the first known
classical Be star hosting a magnetic field.
Key words: stars: magnetic fields / stars: oscillations / stars: winds, outflows / stars: individual: ω Ori
© ESO, 2003
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