event
Thursday 24 Jun 2010: Magnetically-channeled accretion/ejection processes in young stars and their impact on angular momentum evolution
Dr Jerome Bouvier - Observatoire de Grenoble, France
Physics, 4th Floor interaction area 15:30-16:30
Young solar-type stars, the so-called T Tauri stars, possess strong and complex magnetic fields, whose strength and topology are now directly measured through spectropolarimetric techniques. These strong fields disrupt the inner accretion disk over a distance of a few stellar radii, thus leading to magnetic funnel flows connecting the disk inner edge to the stellar surface, to hot spots being the signature of accretion shocks as the free-falling gas hits the stellar surface near the magnetic poles, and to an inner disk warp as the gas and dust in the inner disk is lifted up away from the central plane by the large scale stellar magnetic field. I will provide a summary of the observational evidence we have so far for strong magnetic fields in young stars, inner disk truncation, accretion funnel flows, accretion shocks, and associated outflows. I'll also discuss the evidence for unstabilities in these MHD process that are observed to be strongly variable on timescales ranging from a few hours to several years. Finally, I will discuss the implications of magnetospheric accretion/ejection processes for the angular momentum evolution of young stars.
