Planetary nebulae with Wolf-Rayet-type central stars -- I. The case of
  the high-excitation NGC 2371
  We present the analysis of the planetary nebula (PN) NGC 2371 around the
[Wolf-Rayet] ([WR]) star WD 0722$+$295. Our Isaac Newton Telescope (INT)
Intermediate Dispersion Spectrograph (IDS) spectra, in conjunction with
archival optical and UV images, unveil in unprecedented detail the
high-ionisation of NGC 2371. The nebula has an apparent multipolar morphology,
with two pairs of lobes protruding from a barrel-like central cavity, a pair of
dense low-ionisation knots misaligned with the symmetry axis embedded within
the central cavity, and a high excitation halo mainly detected in He II. The
abundances from the barrel-like central cavity and dense knots agree with
abundance determinations for other PNe with [WR]-type CSPNe. We suggest that
the densest knots inside NGC 2371 are the oldest structures, remnant of a dense
equatorial structure, whilst the main nebular shell and outer lobes resulted
from a latter ejection that ended the stellar evolution. The analysis of
position-velocity diagrams produced from our high-quality spectra suggests that
NGC 2371 has a bipolar shape with each lobe presenting a double-structure
protruding from a barrel-like central region. The analysis of the spectra of WD
0722$+$295 results in similar stellar parameters as previously reported. We
corroborate that the spectral sub-type corresponds with a [WO1] type.
