T Tauri stars microjets resolved by adaptive optics

Using adaptive optics techniques, we have obtained the first [O I] and [S I I] images at 0.1 " (similar or equal to 15 AU) resolution of the jets in CW Tau, DG Tau and RW Aur. In all three jets, the emission is dominated by kn ots and is resolved transversally down to 56 AU with similar innerjet width s of 0.2-0.25 ". The RW Aur and CW Tau jets are straight, their FWHM slowly increasing with distance with opening angles of similar or equal to 3-4 de grees. In contrast, the DG Tau jet seems to be precessing and its FWHM reac hes 1.3 " at 335 AU, where contamination by strong bow-shock wings most lik ely occurs. The widths of the CW Tau and RW Aurjets are strikingly similar to those measured in I-III 30 and I-IL Tau, two active TTs, on similar spat ial scales. The derived upper limit on the density collimation size scale o f similar or equal to 50 AU and intrinsic jet widths of similar or equal to 30 AU over the central 100 AU are in quantitative agreement with predictio ns from current MHD wind models. In DG Tau we confirm the bow-shaped morpho logy and detect a high proper motion (194 km s(-l)) for the knot located at 3.3 ". The properties of this knot strongly support the model of internal working surfaces produced by variable ejection.