In the early stages of star formation, as long as accretion is active, spectacular bipolar gas ejections are always observed, in the form of high velocity and collimated jets and lower velocity and wider molecular outflows. The exact role played by jets and outflows in the evolution of protoplanetary disks and how much mass and angular momentum they carry away from the system remain important unanswered questions.
Recent ALMA observations of the DG Tau B young solar analogue by our team revealed a massive slow and rotating CO outflow, challenging the traditional interpretation of molecular outflows as swept-up material (de Valon et al. 2020, 2022). Instead these results indicate a possible origin in a magnetic disk wind originating from the inner disk radii (within a few au), where the magneto-rotational instability is not effective (dead zone). If confirmed these winds could solve the problem of accretion in the dead zone and strongly impact the evolution of protoplanetary disks. However, the interpretation of a swept-up cavity cannot be completely excluded. Critical constraints on the jet/outflow interaction are missing.
We present preliminary results from JWST Cycle 1 observations of the DG Tau B protostellar outflows. The combined NIRCAM, NIRSpec IFU and MIRI-MRS observations provide constraints on the morphology and excitation conditions of the warm H2 molecular outflow, bridging the gap between the hot axial jet and the cold CO outflow. The JWST dataset is complemented by SINFONI/VLT observations: Thanks to their accurate wavelength calibration on OH sky lines, we study the kinematics of the H2 outflows and constrain their rotation to within a few km/s. These results are confronted to expectations from wind driven cavity and disk wind models and give us important clues to understand the origin of protostellar outflows and their impact on protoplanetary systems.