NAM logo, by David Le Conte

Stellar jets - active at both ends?

David Williams (UCL)

It is well known that jets from young stars may impinge on nearby molecular clouds where they are arrested in shocks that ionise the gas, creating Herbig-Haro (HH) objects. Recently, localised regions of enhanced molecular emission have been observed ahead of some HH objects, within the molecular clouds. We have shown that these enhancements may be created in the photochemistry that occurs when the shock radiation impacts a transient density enhancement within the cloud.

Similar processes may also be occurring near to the star, within the natal core that may be collimating the jet. The jet/core interface is highly turbulent, and the radiation from shocks generated in this interface can stimulate a photochemistry similar to that at the far end of the jet. We have shown that the high HCO+ abundances inferred from observations of stellar cores may arise in this way. The morphology of the HCO+ emission regions, determined from interferometric observations, appear to support this view.

Maintained by Ian Howarth