Result. are presented on spectroscopic observations of near-infrared molecular hydrogen emission lines towards the Herbig-Haro objects HH 1 and HH 7 to 11. The inferred population densities in the observed H2 levels towards HH 1 and HH 11 are well described by pure thermal distributions, and single excitation temperatures provide good fits. None of the levels have a significantly enhanced population density as should occur if non-thermal processes were involved. The H2 emission towards HH 1 arises from collisional excitations in a gas of temperature around 2750K, while contributions from FUV pumping, suggested elsewhere, are not present. The emission from HH 11 arises from gas at similar temperatures, and emission from H2 re-formation is ruled out. Near-infrared emission of [FeII], present towards HH 1 and HH 7 to 11, is used to infer a reddening of EB–V≃0.5mag and an electron density of ne≃5000cm–3 towards HH 1. Towards individual knots in HH 7 to 11, reddenings range from EB–V=2 to 7mag. The H2 and [FeII] observations together suggest the presence of curved J-type shocks, and rule out C-type bow shocks as the origin of the emission.
ISM: clouds - ISM: jets and outflows - ISM: molecules - infrared: interstellar: lines and bands - stars: pre main-sequence