Evidence for an Ionized Rotating Structure Around RW Aur

Abstract

Profiles of the UV semiforbidden lines of C III and Si III of RW Aur have been obtained with the HST/STIS. The C III profile shows two high velocity components at v = +/- 170 km s^-1 and a central one. The Si III profile is very broad (FWHM = 293 km s^-1) and the high velocity components are unresolved. It is shown that the high velocity components are most probably produced in a rotating belt alike the detected in other sources of bipolar outflows. A radius between 2.7 R_* and the corotation radius (6.1 R_*) is derived and a log T_e (K) ~=4.7 and log n_e(cm^-3) = 11.6 are estimated. The belt is clumpy and the most likely source of heating is local X-rays radiation, probably associated with the release of magnetic energy.