Accretion and outflow in TW Hya

Wednesday, 21. October 2015, 16:00 - 17:30
Location library

Hans Moritz Guenther (MIT) - Accretion and outflow in TW Hya


TW Hya is a the closest and arguable best-studied T Tauri star. Since
the disk is already relatively evolved and not very massive, TW Hya
presents a perfect laboratory to study the interaction between accretion
and outflow at the inner edge of the disk. TW Hya is seen pole-on, so
that rotational variability is not an issue.
I present results of a multi-wavelength spectroscopic monitoring
campaign in 2011, including UV, X-ray, optical and IR spectroscopy. Our
data contains a wealth of accretion shock diagnostics (probing the
infall) and traces a wide range of temperatures in the outflow. We find
that all photometric and spectroscopic features evolve in parallel,
indicating that accretion really is the central engine that powers all
other phenomena as well. Despite strong accretion activity, we confirm
the absence of a hot (10^5 K) wind. The most natural explanation for
this is that the outflow originates mostly at the inner disk edge, where
temperatures are lower, and not on the star itself. The
accretion-outflow connection must therefore be facilitated by an
intermediate step, either magnetic fields or radiation power.

: Hans Moritz Guenther