Outflows from young stars : The Rosetta stone of astrophysical Jets?

It can be argued that all astrophysical jets, from lowly sub-stellar objects such as young brown dwarfs to massive black holes at the centre of AGN, are generated by the same basic physical mechanism. While the nature of that mechanism is still debated, jets from young stars may represent our best chance of deciphering it. There are several reasons for this statement. First of all they are nearby, thus affording us not only high spatial resolution studies of the “central engine” but also time-resolved analysis of their kinematics. Moreover as they radiate emission lines, spectroscopy can reveal radial velocities, temperature, density, ion fraction, etc., along their flow. This wealth of data is a challenge to the theorist/computational simulator but also a highly effective means of discriminating between models. In addition, the observations tightly constrain laboratory experiments. Here, I briefly review what is known about conditions in jets from young stars as a guide to experiments, their generation including their link with accretion disks, and their evolution from the earliest proto-stellar to pre-main sequence phase