\begin{table}%t8
\caption{\label{TabLinesPre}Estimated FMK pre-shock ionic abundances $n_{\rm ion}/n_{\rm O}$ computed assuming that the lines originate only in the pre-shock PIR. (See text for details).}
%\centerline
 {\small \begin{tabular}{lllllllll}
\hline\hline\noalign{\smallskip}
Line  & $I/I$(5007~\AA)
      & $T_{\rm e}$, K & $n_{\rm e}$, cm$^{-3}$ & $\varepsilon$, cm$^3$/s
      & IP, eV & $\Delta t$, s & $n_{\rm ion}/n$(O)
      & $n_{\rm element}$/$n$(O) $^{**}$
{\large\strut}\\
\hline
{}[\ion{Ar}{ii}]  6.985~$\mu$m & 0.5
      & $2.0 \times 10^4$ & 100 & $4 \times 10^{-8}$
      &  27.6 & $5 \times 10^6$ & 1.0$^*$ & 0.005 \\
{}[\ion{Ar}{v}]  13.07~$\mu$m & 0.003
      & 7000            & 250 & $8\times10^{-7}$
      &  75.1 & $5\times10^7$ & $8\times10^{-5}$ & 0.005\\
%
{}[\ion{Ne}{ii}] 12.81~$\mu$m & 0.10
      & $1.5\times10^4$ & 150 & $5\times10^{-8}$
      &  41.0 & $1.4\times10^7$ & 0.06  & 0.02  \\
%
{}[\ion{Fe}{ii}] 17.94~$\mu$m & 0.03
      & $2.0\times10^4$ &  50 & $1.1\times10^{-8}$
      &  16.2 & $9\times10^5$ & 5.5$^*$ & 0.005  \\
%
{}[\ion{S}{iii}] 33.48~$\mu$m & 0.04
      & $1.5\times10^4$ & 150 & $3.0\times10^{-7}$
      &  34.8 & $1\times10^7$ & 0.015   & 0.05  \\
%
{}[\ion{Si}{ii}] 34.81~$\mu$m & 0.07
      & $2.0\times10^4$ &  50 & $1.5\times10^{-7}$
      &  16.4 & $1\times10^6$ & 0.7$^*$ & 0.05  \\
%
{}[\ion{O}{iii}] 88.36~$\mu$m & 0.10
      & $1.0\times10^4$ & 200 & $4.0\times10^{-8}$
      &  54.9 & $3\times10^7$ & 1.1     & 1.0\\
\hline
\end{tabular}}
\medskip
$^*$ Shown to arises mostly in the post-shock photoionized region;
see Sect.~\ref{SecPIR}; $^{**}$ atomic number densities with respect to oxygen, see Table~\ref{TabAbund}.
\end{table}