Highly supersonic motions within the outer features of the η Carinae nebulosity

Spatially resolved HIX and [N II] line profiles have been obtained over striking features in the outer regions of the 11 Carinae nebula. The highly irregular outer 'shell' of low-ionization, [N Il]-bright, knots is shown to exhibit radial velocities between -1200 and + 300 kIn S-1 with respect to the systemic radial velocity, over its perimeter. Furthermore, several knots are found which appear to emit only in the HIX line with radial velocities up to -1450 kIn S-I. However, the most intriguing features are a narrow 'spike' that projects through this outer shell, and a faint 'arc' of emission that extends well beyond it. The 'spike', which exhibits a change of radial velocity along its length, could be a narrow collimated jet with an outflow velocity of ~ 1000 kIn S-I. In one interpretation the 'arc' is modelled by a conical outflow, and mechanisms for generating [N II] emission from highly supersonic gas are also discussed.