The Magnetosphere of T Tauri South
Abstract
We report observations of the T Tauri system at 8.4 GHz with a VLBI array comprising the VLBA VLA and Effelsberg 100m telescopes. We detected a compact source offset approximately 40mas from the best optical position of the T Tau Sb component. The other system components (T Tau Sa T Tau N) were not detected in the VLBI data. The compact source is constrained to be less than 10 solar radii in size. The VLA lightcurve shows rapid variability which together with circular polarization and its compact nature indicate that the observed flux arises from a magnetically-dominated region. One flare was observed to have 100% right-hand circular polarization suggestive of a coherent emission process most probably an electron cyclotron maser. With this assumption it is possible to estimate the strength of the local magnetic field to be 1.5-3 kilogauss. Using the assumption that the steady gyrosynchrotron emission must have brightness temperature less than 10 billion Kelvin we argue that this field must be large in size compared to the star.
- Publication:
-
IAU Symposium
- Pub Date:
- 2003
- Bibcode:
- 2003IAUS..221P.166S