Surface magnetic fields as windows to stellar internal structure and evolutionary history
The surface magnetic fields of non-degenerate stars are sensitive probes of their current internal structure and evolutionary histories. During the past decade, comprehensive studies of large-scale stellar surface magnetic field topologies have been achieved using tomographic reconstruction based on high-resolution spectropolarimetric time series observations. On the one hand, these investigations have revealed systematic relationships between field characteristics and the evolutionary situation of cool, low-mass stars. These relationships represent important new observational constraints imposed on dynamo models, and the evolution of dynamo physics through the pre-main sequence to the main sequence. On the other hand, the characteristics of magnetism in higher-mass stars are found be remarkably uniform, at both the pre-main sequence and main sequences phases, over more than 1.5 decades in stellar mass. This fundamental result strengthens the view that these fields are of fossil origin, produced as the consequence of common elements of their evolutionary history predating the earliest observable pre-main sequence phases.
Date: Jeudi, le 30 janvier 2014 Heure: 11:30 Lieu: Université de Montréal Pavillon Roger-Gaudry, local D-460 Contact: Tony Moffat