\begin{table}%t3 \caption{\label{tab:lines}Predicted line fluxes for different models, compared with the observed fluxes.}\vspace*{-2mm} \par %\centering \par \begin{tabular}{lcccc} \hline \hline \noalign{\smallskip} & Model \#1 & Model \#2 & Model \#3 & Observed \\ gas/dust & 1 & 100 & 33 & -- \\ $f_{\rm PAH}$ & 0.01 & 0.0055 & 0.0087 & -- \\ $f_{\rm UV}$ & 0.005 & 0.0 & 0.0 & -- \\ \hline \noalign{\smallskip} Line &\multicolumn{4}{c}{Line Fluxes $\rm[10^{-18}~W/m^2]$} \\ \hline [OI] 63.2~\mic & 154 & 71.6 & 71.6 & 71.7 \\ \par [OI] 145.5 ~\mic & 5.17 & 10.1 & 7.01 & $<$10.4 \\ \par [CII] 157.7~\mic & 4.58 & 0.04 & 0.06 & $<$6.4 \\ o-\water~179.5~\mic & 5.66 & 5.15 & 1.76 & $<$8.8 \\ \hline \noalign{\smallskip} $^{12}$CO 2 $\rightarrow$ 1 & 0.060 & 0.092 & 0.093 & 0.093 \\ $^{13}$CO 2 $\rightarrow$ 1 & 0.011 & 0.059 & 0.048 & 0.048 \\ $^{12}$CO$/^{13}$CO & 5.69 & 1.55 & 1.92 & 1.94 \\ \hline \end{tabular}\vspace*{-2mm} \tablefoot {The best fit is obtained by model~\#3. All models in this table have turbulent line broadening $v_{\rm turb}$~=~0.15~km~s$^{-1}$.}\vspace*{-4mm} \end{table}