\begin{table}%t4
\caption{\label{tab4}Input parameters for the model nebula (CLOUDY).}
%\centering
\par
\begin{tabular}{ll}
\hline\hline
Radial density profile &  ionized gas = Fig.~\ref{fig13}; cf. Sect. 7.1\\
&neutral gas = cf. Sects. 3 and 4\\
\\
Chemical abundances:   & \\
~~ C, Cl, K, Ca, Mg, Si & Hyung \& Aller (\cite{Hyung1997}) model B\\
~~ He, N, O, Ne, S, Ar & Table~\ref{tab3} (second row)\\
~~ other elements      & PN (CLOUDY default)\\
&\\
Dust                   & PN (CLOUDY default)\\
&\\
Local filling factor         & 1.0 \\
&\\
&blackbody distribution\\
Exciting star   & $T_*=170~000$ K \\
& log~$L_*/L_\odot= 2.75$\\
&\\
Distance& 2.0 kpc\\
\hline
\end{tabular}
\end{table}