Why are accreting T Tauri stars less luminous in X-rays than non-accretors?
Scott Gregory, University of St Andrews Accreting T Tauri stars show lower levels of X-ray activity than non-accretors. To explain this we have combined, for the first time, a radiative transfer code with an accretion model that considers magnetic fields extrapolated from surface magnetograms obtained from Zeeman-Doppler imaging. Such fields consist of compact magnetic regions close to the stellar surface, with extended field lines interacting with the disk. We study the propagation of coronal X-rays through the magnetosphere, and demonstrate that they cannot penetrate the dense material in accretion columns. The reduction in L$_X$ depends strongly on the field geometry, and may explain why CTTs show a larger scatter in L$_X$ values compared to WTTs. The Role of Stellar Winds in the Star-Disk Interaction Sean Matt, University of Virginia Stellar winds may be important for angular momentum transport from accreting young stars, but the nature of these winds is still not well-understood.
