| Abstract
| - Spatially resolved Hα and [N ii] line profiles have been obtained over striking features in the outer regions of the η Carinae nebula. The highly irregular outer ‘shell’ of low-ionization, [N ii]-bright, knots is shown to exhibit radial velocities between −1200 and + 300 km s−1 with respect to the systemic radial velocity, over its perimeter. Furthermore, several knots are found which appear to emit only in the Hα line with radial velocities up to − 1450 km s−1. 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 km s−1. 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.
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