Herbig-Haro Objects are high-speed clumps of molecular and atomic gas. They are often "bow" shaped and the gas is "shock" excited. They occur near protostars and young stars. Sometimes they are detected near the surface of a cloud, betraying the presence of a hidden protostar. They appear to be driven by jets from a forming star, being the result of the impact of the jets with the environment. They provide a means of investigating the behaviour, composition and structure of star-forming regions.
The shock absorber : evidence for HIGH Magnetic Fields in Jets (PDF file).
Last Revised: 2009 November 6th