The nature and structure of the emission line nebula K 3‐35: a very young planetary nebula with precessing bipolar jet‐like outflows?

We present Hα, [N  II ]6583 and 6‐cm continuum images of the emission line nebula K 3‐35. The optical images reveal an extended nebula (size ≃ 11 × 9 arcsec 2 in [N  II ]) in which most of the emission originates in a very narrow (width 0.7–1.3 arcsec) S‐shaped region which extends almost all along the nebula (≃ 7 arcsec). The 6‐cm continuum emission also arises in this narrow region, which is characterized by an exceedingly high point‐symmetry and systematic and continuous changes of the orientation with respect to the nebular centre. The properties of the narrow region suggest that it represents a system of precessing bipolar jet‐like components. Two low‐excitation, compact bipolar knots near the tips of the jet‐like components are observed in the deduced [N  II ]/Hα image ratio. These knots may be generated by the interaction of the collimated outflows with surrounding material. A comparison of the optical and radio images shows the existence of differential extinction within the nebula. Maximum extinction is observed in a disc‐like region which traces the equator of the elliptical shell previously observed at 20‐cm continuum. All available data strongly suggest that K 3‐35 is a very young planetary nebula in which we could be observing the first stages of the formation of collimated outflows and point‐symmetric structures typically observed in planetary nebulae. The properties of the jet‐like components in K 3‐35 are in good agreement with models of binary central stars in which highly collimated outflows originate either from a precessing accretion disc or via magnetic collimation in a precessing star.