\begin{table}%t3
\caption{Derived nebular properties. $L_{\rm cs}$ is the luminosity of the central star.  Note that H$\beta$~fluxes are derived from the H$\alpha$~fluxes assuming standard case~B
recombination.}\label{tab:derived}
%\centering
\small
\begin{tabular}{lccc} 
\hline \hline
                              &  N5236-254    & N5236-487     & N3621-1106 \\
\hline	          
 & & & \\[-8pt]
$L$ (H$\alpha$) [$10^{35}$ erg s$^{-1}$]& 5.14 $\pm$ 0.85 & 4.44 $\pm$ 0.73 &  -- \\
$L$ (H$\beta$) [$10^{35}$ erg s$^{-1}$]$^\star$ & 1.80 $\pm$ 0.30 & 1.56 $\pm$ 0.25 &  -- \\
$L$ ([O III])                   & 6.11$\pm$0.99 & 5.10 $\pm$ 0.84 & 18.7 $\pm$ 4.49 \\
$M_{5007}$                   & $-3.01\pm0.18$ & $-2.82\pm0.18$ & $-4.23\pm0.26$ \\
Excitation parameter ($E$)    & 1.52 $\pm$ 0.14 & 1.47 $\pm$ 0.14 &  -- \\
$\log T_{\rm eff}$ [K]        & 4.66 $\pm$ 0.02 & 4.65 $\pm$ 0.02 &  -- \\
$\log L_{\rm cs}$ [$L_{\odot}$]  & 3.79 $\pm$ 0.08 & 3.73 $\pm$ 0.08 &  -- \\
\hline
\end{tabular}
\end{table}