Tomography of the unique on-going jet in the planetary nebula NGC 2392
  Jets (fast collimated outflows) are claimed to be the main shaping agent of
the most asymmetric planetary nebula (PNe) as they impinge on the circumstellar
material at late stages of the asymptotic giant branch (AGB) phase. The first
jet detected in a PN was that of NGC 2392, yet there is no available image
because its low surface brightness contrast with the bright nebular emission.
Here we take advantage from the tomographic capabilities of GTC MEGARA
high-dispersion integral field spectroscopic observations of the jet in NGC
2392 to gain unprecedented details of its morphology and kinematics. The jet of
NGC 2392 is found to emanate from the central star, break through the walls of
the inner shell of this iconic PN and extend outside the nebula's outermost
regions with an S-shaped morphology suggestive of precession. At odds with the
fossil jets found in mature PNe, the jet in NGC 2392 is currently being
collimated and launched. The high nebular excitation of NGC 2392, which implies
a He$^{++}$/He ionization fraction too high to be attributed to the known
effective temperature of the star, has been proposed in the past to hint at the
presence of a hot white dwarf companion. In conjunction with the hard X-ray
emission from the central star, the present-day jet collimation would support
the presence of such a double-degenerate system where one component undergoes
accretion from a remnant circumbinary disk of the common envelope phase.
