Catching a grown-up starfish planetary nebula II. Plasma analysis and
  central star properties of PC 22
  After performing the morpho-kinematic analysis of the planetary nebula (PN)
PC 22, we now present its nebular and stellar analysis. The plasma
investigation relies on the novel use of a Monte Carlo analysis associated to
the PyNeb code for the uncertainty propagation. The innermost region of the
nebula shows electronic temperatures $T_{\rm e}$ $\approx$ 10,800~K using [NII]
and $\approx$ 13,000 K using [OIII] and electronic densities $n_{\rm e}$
$\approx$ 600~cm$^{-3}$. We also used for the first time a Machine Learning
Algorithm to calculate Ionisation Correction Factors (ICFs) specifically
adapted to PC 22. This has allowed us to have pioneer ICFs for (S$^{+}$ +
S$^{++}$)/O$^{++}$, Cl$^{++}$/O$^{++}$, and Ar$^{3+}$+Ar$^{4+}$, as well as a
possible new determination for the total abundance of neon. The study of the
stellar spectrum revealed the presence of broad emission lines consistent with
a Wolf-Rayet-type [WR] classification and more precisely a [WO1]-subtype based
on different qualitative and quantitative criteria. This classification is also
coherent with the high stellar temperature derived from the reproduction of the
ionization state of the gas with the Mexican Million Models database (3MdB) and
the best fit model obtained with the NLTE model atmosphere code PoWR. PC 22 is
therefore a new addition to the [WO1]-subtype PNe.
