\begin{table}%t9
%\centering
\par
\caption{Logarithmic extinction constant \cbeta, and electron temperatures  
and densities. Errors on temperatures are within 500 Kelvin.\label{physical} }  
\begin{tabular}{lccccc}   
\hline \hline  
Object &\cbeta\ & $T_{\rm e}$(\oiii) & $T_{\rm e}$(\nii) & $N_{\rm e}$(\sii)  & $N_{\rm e}$(\cliii)     \\  
name   &        &    (K)    &   (K)    & (cm$^{-3}$)  & (cm$^{-3}$)            \\   
\hline	        		             
DdDm1  &   --    & 12~200    &    --      &     --    &    3700    \\    
IC~5117 &  1.30  & 12~500    & 13~500   &     --    &   38~000    \\  
NGC~6833&  0.34  & 13~200    & 15~400   & $>$10~000 &      --       \\  
M~1--71  &  2.44  &  9800    & 10~200   & $>$10~000 &      --     \\  
\hline  
\end{tabular}  
\end{table}