\begin{table}%t3 %\centering \par \caption{\label{tab:dusty}Best fit D{\sc usty} model input parameters and results for the physical structure of the four molecular envelopes in Serpens.} \center\begin{tabular}{l r r r r r} \hline\hline\noalign{\smallskip} Property & SMM1 & SMM3 & SMM4 & S68N & IRAS2A \\ \hline $L$ ($L_\odot$) & 37 & 2.0 & 6.3 & 3.6 & 21 \\ $d$ (pc) & \multicolumn{4}{c}{230} & 250\\ %\hline $p$ & 2.1 & 1.6 & 1.8 & 1.8 & 1.9\\ $\tau$(100~$\mu$m) & 3.8 & 1.1 & 3.0 & 3.4 & 1.8\\ $Y$ (=$r_{\rm in}$/$r_{\rm out}$) & 400 & 1000 & 1000 & 800 & 500 \\ %\hline $r_{\rm in}$ (AU) & 49 & 14 & 17 & 18 & 31.3 \\ $r_{\rm out}$ (10$^4$~AU) & 2.0 & 1.4 & 1.7 & 1.4 & 1.6 \\ $n_{\rm in}$ (10$^9$~cm$^{-3}$) & 1.7 & 0.94 & 2.8 & 3.0 & 1.0 \\ $n_{\rm 1000~AU}$ (10$^6$~cm$^{-3}$) & 3.0 & 1.0 & 1.9 & 2.2 & 1.4 \\ $N$(H$_2$) (10$^{24}$~cm$^{-2}$) & 1.1 & 0.33 & 0.89 & 1.0 & 0.53 \\ Envelope mass, $T > 10$~K ($M_\odot$) & 4.1 & 2.5 & 3.9 & 3.6 & 2.2 \\ \hline \end{tabular} \end{table}