Jets, Disk Winds, and Warm Disk Coronae in Classical T Tauri Stars

Abstract

Arguments, based on analysis of the forbidden line emission, are summarized that point to two components of mass ejection in classical T Tauri stars. A low-speed wind originates from the accretion disk at between ~ 0.05 AU and ≳ 3 AU from the star, and a high-speed flow, which becomes collimated into a jet within ≲ 100 AU, originates as a wind from either the star or the very inner part of the accretion disk. The [OI] λ5577 emission in the low-speed component also requires the presence of a warm disk corona, with an electron density of ~ 10⁷ cm^-3 and a temperature of ~ 8000 K. Additional indication of a warm disk corona comes from analysis of the central absorptions seen in the profiles of the hydrogen Balmer lines. The need to heat the disk corona implies that a substantial fraction of the energy released in the accretion of matter through the disk may be dissipated at the disk surface.