Inivited talk - Theoretical aspects of asteroseismology

For a few decades, a large international community is working at the development of stellar seismology, intending to open a new window on the structure and evolution of stars, with the necessary parallel development of new observational techniques, modeling tools and methods for diagnostics and interpretation. This new window is associated with new observables, characterizing the oscillations (frequencies, amplitudes, line profiles,...) which are sensitive to the stellar interior and thus very complementary with surface observables, associated to astrometry, spectropolarimetry or interferometry. Strong efforts have been made on both the observational side, to bring observational data suitable for seismic interpretation, and on the theoretical side, to refine stellar evolution models and bring them at the level of precision required by seismology sensitivity. However, ultimately, stellar seismology resides in our practical ability to confront observations and models and reach a seismic diagnostic. I will focus here on this interpretation aspect of stellar seismology, taking examples selected in the recent literature to illustrate the present problematics, the difficulties and the present approach of the problem. I hope to help this way the participants of this session, especially the youngest and the new comers to this field, to get some references and keys to appreciate the different works which will be presented in this session and identify how they do participate to the development of this field. I will first briefly sketch what the goals of stellar seismology are. Then I will introduce some of the most commonly used tools and come to a few hopefully illustrative tentative applications selected in the literature. Finally, I will propose a point of view on the present state of the art and prospects.