Spectroscopic diagnostics of T Tauri inner winds

The role of the star-disk interaction region in launching the high velocity component of accretion-driven outflows is examined. Spectroscopic indicators of high velocity inner winds have been recognized in T Tauri stars for decades, but identifying the wind launch site and the accompanying mass loss rates has remained elusive. A promising new diagnostic is He I λ10830, whose metastable lower level results in a powerful probe of the geometry of the outflowing gas in the interaction region. This, together with other atomic and molecular spectral diagnostics covering a wide range of excitation and ionization states, suggests that more than one launch site of the innermost wind is operational in most accreting stars.