AN EPISODIC JET FROM ETA-CARINAE

The jet-like feature which points away from the extremely luminous sta r eta Carinae out to a prominent ionized knot has now been successfull y imaged with the New Technology Telescope (NTT). Moreover, high dispe rsion, spatially resolved measurements of the profiles of its emission lines with the Manchester echelle spectrometer on the Anglo Australia n telescope (AAT) and the EMMI spectrometer on the NTT confirm that it has many of the characteristics expected of a true interstellar jet; it is emerging along the minor axis of the surrounding nebulosity at a lmost-equal-to 1400 km s-1 away from eta Car yet exhibits a velocity d ispersion of only 40 km s-1 and is bright in the light of the low ioni zation [NII]6584angstrom emission line. One possible model has the ion ized knot as the working surface of the jet's interaction with ambient gas for the knot has an electron density of 4200 cm-3 and a measured velocity of 1374 km s-1 from eta Car at an angle of 27-degrees to the plane of the sky. Alternatively, both the knot and the jet-like featur e could be working surfaces of shocks driven into separate 'bullets' o f an unseen episodic jet.