Shocks and Star Formation
Forming stars, whether high- or low-mass, drive shocks into the surrounding medium through winds and jets launched close to the accreting protostar. The winds and jets interact with the infalling envelope and the surrounding cloud material on scales from less than 100 AU to several parsec. How the shocks influence the quiescent material depends, in particular, on the shock velocity and the ambient magnetic field and gas density, and interpreting any observations of shocks require a detailed comparison to sophisticated shock models. Through model comparison it is possible to infer how the shocks affect and feed back on the star formation process.
I will discuss observations of shocks in a nearby massive star-forming region, the Orion Molecular Cloud, as well as shocks in low-mass protostars. I will do so by first focusing on shock-modeling techniques and how 2D/3D models can be created from 1D simulations. Second I will discuss how one particular shock tracer, water, has changed the way we view feedback from low-mass protostars on their surrounding envelope, both on small and large scales. Finally I will discuss how high-resolution ALMA data can be used to directly image the feedback, and I will project these results to larger scales where interacting galaxies drive kilo-parsec scale shocks into their interstellar media.