\begin{table}%t2
%\centering
\par
\caption{Sample of sources.} \label{tsource}
\small
\begin{tabular}{lllrrrrrrl} \hline\hline
Source & RA (J$2000$) & Dec (J$2000$) & $V_{\rm LSR}$ & $L_{\rm bol}$ & Distance & $M_{\rm env}$ & $r_{\rm env}$ & $N({\rm H_2})$ & Type \\ 
 & (hh mm ss) & (dd mm ss) & (km/s) & ($L_{\sun}$) & (pc) & ($M_{\sun}$) & (AU) & (10$^{23}$~cm$^{-2}$) &     \\ \hline\noalign{\smallskip}
AFGL 2591$^a$ & 20 29 24.7 & $+$40 11 19 & --5.5 & $2 \times 10^4$   & 1000 & 44   & 27~000 & 1.0  & HMPO \\
W3 IRS5$^a$   & 02 25 40.6 & $+$62 05 51 & --39.0 &$1.7 \times 10^5$ & 2200 & 262  & 60~000 & 6.6 & HMPO \\
IRAS 16293--2422$^b$ & 16 32 22.8 & $-$24 28 33 & 4.0 &  27 & 160  & 5.4   & 8000 & 16.0 & Class 0 \\ 
N1333-I2$^c$  & 03 28 55.4 & $+$31 14 35 & 7.0 & 16 & 220 & 1.7   & 21~000 & 5.5  & Class 0 \\
N1333-I4A$^c$ & 03 29 10.3 & $+$31 13 31 & 7.0 & 6 & 220 & 2.3   & 24~000 & 22.0 & Class 0 \\
L1448-C $^c$  & 03 25 38.8 & $+$30 44 05 & 5.0 & 5 & 220 & 0.93  & 15~000 & 1.7  & Class 0 \\
L483$^c$      & 18 17 29.8 & $-$04 39 38 & 5.2 & 9 & 200 & 1.1   & 32~000 & 9.3  & Class 0 \\
L723$^c$      & 19 17 53.7 & $+$19 12 20 & 11.2 & 3 & 300 & 0.62  & 21~000 & 3.4  & Class 0 \\
SMM4$^d$      & 18 29 56.7 & $+$01 13 15 & 7.9 & 11 & 250 & 5.8   & 9300  & 12.0 & Class 0 \\
V1057 Cyg$^e$ & 20 58 53.7 & $+$44 15 28 & 4.1 & 70 & 650 & 1.4   & 15~000 & 0.5  & FU Ori \\
L1489$^c$     & 04 04 43.0 & $+$26 18 57 & 7.0 & 3.7 & 140 & 0.097 & 9400  & 1.0  & Class I \\ \hline
\end{tabular}
\begin{list}{}{}
\item[] The luminosity and envelope parameters are from $^a$ van der Tak et~al. (\cite{vv99}, \cite{ve00}); 
$^b$  Sch\"oier et~al. (\cite{sj02}); $^c$ J{\o}rgensen et~al. (\cite{js02}); $^d$~Pontoppidan et~al. (\cite{pv04}); $^e$ this paper. The H$_2$ column densities are calculated by integrating the power-law 
density distribution out to $r_{\rm env}$ ($N({\rm H_2}) = \int n(r)~{\rm d}r$).
\end{list}
\end{table}