SIMBAD references

Continuum-subtracted dereddened images in the light of several atomic lines show the presence of an extended bipolar nebula surrounding η Carinae with size ∼100x45arcsec² (1.3x0.5pc²). This feature is best delineated in [Oiii] 5007. The geometrical disposition and mass of the shell suggest that it was formed by mass ejections from η Carinae. The dynamic age of the nebula is ∼13000/V₇yr, where V₇ is the mean expansion velocity in 100km.s^–1, and its mass is between 5 and 10M_☉. The nebula is photoionized and composed of unprocessed material. The major axes of the nebula and of the Homunculus are nearly perpendicular. We also report the discovery of elongated emission knots prominent in [Nii] located 64 to 100arcsec away from η Carinae, which implies that they were ejected either centuries ago or at a more recent date but with extremely large velocities.