EDP Sciences
Free access
Issue
A&A
Volume 455, Number 2, August IV 2006
Page(s) 621 - 637
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:20065269


A&A 455, 621-637 (2006)
DOI: 10.1051/0004-6361:20065269

Acoustic oscillations of rapidly rotating polytropic stars

II. Effects of the Coriolis and centrifugal accelerations
D. Reese, F. Lignières and M. Rieutord

Laboratoire d'Astrophysique de Toulouse et Tarbes, UMR 5572, Université Paul Sabatier Toulouse 3, Observatoire Midi-Pyrénées, 14 avenue É. Belin, 31400 Toulouse, France
    e-mail: daniel.reese@ast.obs-mip.fr

(Received 24 March 2006 / Accepted 12 May 2006 )

Abstract
Context.With the launch of space missions devoted to asteroseismology (like COROT), the scientific community will soon have accurate measurements of pulsation frequencies in many rapidly rotating stars.
Aims.The present work focuses on the effects of rotation on pulsations of rapidly rotating stars when both the Coriolis and centrifugal accelerations require a non-perturbative treatment.
Methods.We develop a 2-dimensional spectral numerical approach which allows us to compute acoustic modes in centrifugally distorted polytropes including the full influence of the Coriolis force. This method is validated through comparisons with previous studies, and the results are shown to be highly accurate.
Results.In the frequency range considered and with COROT's accuracy, we establish a domain of validity for perturbative methods, thus showing the need for complete calculations beyond $v \sin i=50\,\mathrm{km\,s}^{-1}$ for a $R = 2.3\,R_\odot$, $M=1.9\,M_\odot$ polytropic star. Furthermore, it is shown that the main differences between complete and perturbative calculations come essentially from the centrifugal distortion.


Key words: stars: oscillations -- stars: rotation



© ESO 2006