Volume 587, March 2016
|Number of page(s)||24|
|Section||Stellar structure and evolution|
|Published online||26 February 2016|
Asymptotic theory of gravity modes in rotating stars
I. Ray dynamics
1 Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching bei München, Germany
2 Université de Toulouse, UPS-OMP, IRAP, 31028 Toulouse, France
3 CNRS, IRAP, 14 avenue Édouard Belin, 31400 Toulouse, France
Received: 13 November 2015
Accepted: 22 December 2015
Context. The seismology of early-type stars is limited by our incomplete understanding of gravito-inertial modes.
Aims. We develop a short-wavelength asymptotic analysis for gravito-inertial modes in rotating stars.
Methods. The Wentzel-Kramers-Brillouin approximation was applied to the equations governing adiabatic small perturbations about a model of a uniformly rotating barotropic star.
Results. A general eikonal equation, including the effect of the centrifugal deformation, is derived. The dynamics of axisymmetric gravito-inertial rays is solved numerically for polytropic stellar models of increasing rotation and analysed by describing the structure of the phase space. Three different types of phase-space structures are distinguished. The first type results from the continuous evolution of structures of the non-rotating integrable phase space. It is predominant in the low-frequency region of the phase space. The second type of structures are island chains associated with stable periodic rays. The third type of structures are large chaotic regions that can be related to the envelope minimum of the Brunt-Väisälä frequency.
Conclusions. Gravito-inertial modes are expected to follow this classification, in which the frequency spectrum is a superposition of sub-spectra associated with these different types of phase-space structures. The detailed confrontation between the predictions of this ray-based asymptotic theory and numerically computed modes will be presented in a companion paper.
Key words: asteroseismology / chaos / waves / stars: oscillations / stars: rotation
© ESO, 2016
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.