HL Tau SO2 14(0-14)-13(1,13) datacube

The measured rotational temperatures and radial velocities are consistent with this view. In contrast to younger Class 0 sources, these shocks are confined to the specific disk region impacted by the streamer. In HL Tau, the known accreting streamer induces a shock in the disk outskirt, and the released SO and SO_2_ molecules spiral toward the star in a few hundreds years.

These results suggest that shocks induced by late accreting material may be common in the disks of young star-forming regions with possible consequences on the chemical composition and mass content of the disk. They also highlight the importance of SO and SO_2_ line observations to probe accretion shocks from a larger sample.