Solar and Stellar Interiors
In collaboration with the University of Göttingen
Research tools: Helioseismology and Asteroseismology
One of the most important unsolved problems in solar physics today is the origin of the Sun’s eleven-year magnetic cycle. More generally, activity cycles in cool stars with convective envelopes are not understood. These cycles are expected to be the result of the interplay between flows (e.g., rotation, meridional circulation, convection) and magnetic fields and are described by dynamo models. It is not clear, however, how and where the dynamos operate, and what sets the periods of activity cycles. The reason for this lack of understanding is the absence of sufficient empirical information about subsurface dynamics in solar and stellar interiors.
Helioseismology is the use of stochastically excited solar oscillations as probes of the interior of the Sun. Asteroseismology is a generalization of helioseismology to the study of oscillations of other stars. These tools allow us to test and refine the theory of stellar structure and evolution and to study thermal structures and flows in the interior of the Sun and stars, thereby bringing us closer to understanding solar and stellar magnetism. Further, asteroseismology allows us to place the Sun in the context of other similar stars and to study the possible futures and pasts of the Sun.