François Lignières (IRAP), Jérôme Ballot (IRAP)

Seismology of intermediate-mass and massive stars is limited by our lack of understanding of the effect of fast rotation on gravity modes. In particular, in this regime perturbative methods are unable to identify observed modes. We therefore develop an asymptotic theory for adiabatic gravito-inertial modes in uniformly rotating stars. We first derived a generalized dispersion equation taking the Coriolis force and the centrifugal deformation into account. The corresponding ray dynamics allowed us to explore the structure of the phase space thanks to a ray-tracing code. We observed three coexisting types of structures: (i) nearly integrable structures similar to non- rotating structures, (ii) island chains around stable periodic orbits, (iii) large chaotic zones. These three different types of structures are expected to give three different families of modes.

Stéphane Mathis, François Lignières, Jérôme Ballot, Pierre-Marie Culpin

Most of the information we have about the internal rotation of stars comes from modes that are weakly affected by rotation, for instance thanks to rotational splittings. In contrast, we present here a method (based on the asymptotic theory of Prat et al. 2016, A&A, 587, A110) which allows us to analyze the signature of rotation where its effect is the most important, that is in low-frequency modes that are strongly affected by rotation.