Issue |
A&A
Volume 459, Number 2, November IV 2006
|
|
---|---|---|
Page(s) | 589 - 596 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20064980 | |
Published online | 12 September 2006 |
An asteroseismic study of the β Cephei star β Canis Majoris
1
Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium e-mail: anwesh.mazumdar@yale.edu
2
Astronomy Department, Yale University, PO Box 208101, New Haven, CT 06520-8101, USA
3
Department of Astrophysics, University of Nijmegen, PO Box 9010, 6500 GL Nijmegen, The Netherlands
Received:
7
February
2006
Accepted:
11
July
2006
Aims.We present the results of a detailed analysis of 452 ground-based, high-resolution high S/N spectroscopic measurements spread over 4.5 years for β Canis Majoris with the aim of determining the pulsational characteristics of this star, and then using them to derive seismic constraints on the stellar parameters.
Methods.We determined pulsation frequencies in the Si III 4553 Å line with
Fourier methods. We identified the m-value of the modes by taking the
photometric identifications of the degrees into account. To this
end we used the moment method together with the amplitude and phase
variations across the line profile. The frequencies of the identified
modes were used for a seismic interpretation of the structure of the
star.
Results.We confirm the presence of the three pulsation frequencies already
detected in previous photometric datasets:
(
),
(
), and
(
). For the two modes with the highest
amplitudes, we unambiguously identify
and
. We cannot conclude anything for the third mode
identification, except that
. We also deduce an equatorial
rotational velocity of
for the star. We show that the
mode f1 must be close to an avoided crossing. Constraints on the mass
(
), age (
Myr), and core overshoot
(
) of β CMa are obtained from seismic modelling
using f1 and f2.
Key words: stars: early-type / stars: individual: β Canis Majoris / techniques: spectroscopic / stars: oscillations
© ESO, 2006
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