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Astron. Astrophys. 361, 1112-1120 (2000)

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7. Conclusions

The radial density distribution of the ionized gas in the high excitation PN NGC 1501 presents density peaks up to 1400 cm-3; they have steep outwards profiles and extended inwards tails probably originated by Rayleigh-Taylor instability and winds interaction.

By comparing the H[FORMULA] and [OIII] emission line profiles we derive an electron temperature of 11500 K and a turbulence of 18 km s-1, but large, small scale fluctuations of both these quantities are present in the ionized gas.

The complex expansion velocity field observed in this nebula is fitted by an ellipsoid of moderate ellipticity, deformed by a pair of large lobes along both the major and intermediate axes and by a multitude of minor bumps scattered on the whole nebular surface.

The peculiar morphology of NGC 1501 can be qualitatively explained in terms of interaction of the nebular gas with the intense and fast wind from the WC4/OVI central star.

The exquisitely observational nature of this paper exempts us for hunting sophisticate evolutionary models; since our race is finished, we strecth the baton to someone else (hoping to see a "modellist" ready to catch it and to put on a winning burst of speed).

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© European Southern Observatory (ESO) 2000

Online publication: October 10, 2000