Touching the inside of a convecting star and its magnetic dynamo
Juri Toomre
Joint Institute for Laboratory Astrophysics (JILA)
Date and time:
Friday, January 18, 2013 - 1:15pm
Abstract:
Stars are the primary builders of magnetism in our Universe, expelling some of it through their winds and explosions, or leaving it behind in the compact ashes of their lives. The rich magnetism displayed by many stars, including our Sun, must have much of its origin in dynamo action proceeding within their convection zones involving highly turbulent flows influenced by rotation. Rapid advances in supercomputing have allowed us to carry out 3-D global simulations to study the nature of magnetic dynamo action and differential rotation that can be achieved in G-type stars like the Sun by convection in their outer envelopes, and also by core convection in more massive A-type stars. The resulting magnetic fields can exhibit remarkable large-scale structure along with temporal flips and even cycles. Such theoretical modeling of dynamics deep within a star will be contrasted with evidence now emerging from seismic probing of some of these stars.