Evidence for an ionized rotating structure around RW Aur

Abstract

Profiles of the UV semiforbidden lines of C III](1908) and Si III](1892) of RW Aur have been obtained with the HST/STIS. The C III](1908) profile shows two high velocity components at v = +/- 170 km s(-1) and a central one. The Si III](1892) 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) similar or equal to 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.