The flywheels of helios: making sense of how the Sun (and other stars) go round.
March 14, 2011
Abstract: Helioseismology has become precision tool that has allowed the inner rotation pattern of the Sun to be elucidated. While the radiative zone is well modeled by solid body rotation, the turbulent convective zone shows a regular pattern of differential rotation. Surfaces of constant angular velocity are, roughly speaking, poleward-opening cones, coaxial with the rotation axis. In this talk, I will show how a few simple physical ideas and mathematical techniques are able to reproduce these observations with striking fidelity. The inner and outer boundaries of the convective zone exhibit strong deviations from the conical pattern; these ‘anomalies’ offer valuable clues to the stresses that are present in these regions. If correct, the principles of the theory should be applicable to a wide class of stars, including those with fully convective envelopes, and possibly to the internal rotational dynamics of convective planets.