A precessing, variable velocity jet model for DG Tauri

Abstract

We present a first attempt at reproducing the morphology and kinematical properties of the DG Tau microjet using a 3D hydrodynamical numerical simulation of a precessing, variable velocity jet. Synthetic maps and position-velocity diagrams in H α and [O I] λ 6300 are calculated and compared with recent imaging and spectro-imaging observations (Lavalley-Fouquet et al. [CITE]; Dougados et al. [CITE]). Several observed properties are qualitatively reproduced, such as the knot separation, width, and asymmetric morphology, and the increase in ionization fraction and decrease in electronic density away from the star. However, the predicted kinematics in the region between the two jet knots differs from the observed behaviour. This discrepancy probably results from our simple assumption of a sinusoidal velocity variability, and points to a more complex velocity time-variability in the jet from DG Tau.