Letter to the Editor

3-D numerical simulations of rotating jets

The case of the DG Tau microjet

¹ LATO-DCET-UESC, Rodovia Ilhéus - Itabuna, km 16, Ilhéus, Bahia, CEP 45662-260, Brazil e-mail: hoth@uesc.br
² IAG-USP, Rua do Matão, 1226, Cidade Universitária, São Paulo, São Paulo, CEP 01060-970, Brazil e-mail: dalpino@astro.iag.usp.br

Received: 29 April 2004
Accepted: 6 September 2004

Abstract

We here present results of three-dimensional Smoothed Particle hydro and magnetohydrodynamics simulations of rotating jets, also including the effects of radiative cooling, precession and velocity variability. Using initial conditions and parameters which are particularly suitable for the DG Tau microjet, we have been able to approximately reproduce its complex knotty morphology and kinematics. We have also obtained radial velocity maps which are in good agreement with the data obtained by Bacciotti et al., thus indicating that their interpretation that the DG Tau microjet is rotating is correct. Finally, we have found that a magnetic field of the order of ≈0.5 mG is sufficient to collimate the jet against the lateral expansion that is caused by the centrifugal forces.