Shocked Molecular Hydrogen Associated with Herbig-Haro Objects and Molecular Outflows: The Cepheus-A Flow.

Imaging of the near-infrared lines of shock-excited molecular hydrogen provides a high angular resolution probe of the morphology of shock waves produced by outflows ramming dense and obscured molecular gas. Comparisons with mm-wave CO and optical data suggest that time variations in the mass loss rate, inhomogeneities in the ambient cloud, and variations in the shock strength and excitation conditions are needed to explain the complex morphology of the observed shocks. We discuss new IR imaging of the outflow associated with the Cepheus-A star forming region.