\begin{table}%[hbtp]%T9
    \caption{Molecular abundances and abundance ratios: outer envelope.}
    \label{tab:abs}
    %\centerline
{
    \begin{tabular}[lrrrrrrrrrrrrr]{lrrrrrrrrrrrrr}
\hline \hline
\noalign{\smallskip}
Source      & SO & SO$_2$ & OCS & CS$^a$ & H$_2$S & H$_2$CS & NS  & HCS$^+$ 
            & SO/ & \soo/ & SO/ & \hhs/ & NS/ \\
 &$10^{-9}$&$10^{-9}$&$10^{-9}$&$10^{-9}$&$10^{-9}$&$10^{-10}$&$10^{-11}$&$10^{-10}$
            & \soo & CS   & CS  & CS    & CS\\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
%               SO   SO2     OCS   CS   H2S   H2CS   NS    HCS+ 
NGC 7538 IRS9 & 1  & 0.5   &  2  & 10 &  3   & 10 & 1     & 5     & 2 &0.05&0.1&0.8& 0.001 \\
S140 IRS1     & 2  & 1     &$<$2 &  5 &  2   &  7 & 1     & 5     & 2 &0.2&0.4&0.8& 0.002 \\
W3 IRS5       & 10 & 10    & 0.5 &  5 &  3   &  3 & ...   & 0.2   & 1 & 2 & 2 & 2 & ... \\
MonR2 IRS3    & 5  & 1     & ... &  5 & $<$2 &  7 &$<$1   & ...   & 5 &0.2& 1 &$<$0.8& ... \\
AFGL 2136     & 1  & 0.5   & ... &  4 & $<$1 &  3 &$<$0.5 & 1     & 2 &0.1&0.25&$<$0.5&$<$0.001\\
W33A          & 1  & 1     & 20  &  5 &  3   & 13 & 2     & 2     & 1 &0.2&0.2& 2 & 0.004 \\
AFGL 2591     & 10 & 2     & 10  & 10 &  8   &  3 & 0.5   & 2     &10 &0.1& 1 & 2 & 0.0005 \\
NGC 7538 IRS1 & 5  & 1     &  2  & 10 &  3   & 10 & 1     & 2     & 5 &0.1&0.5&0.8& 0.001 \\
NGC 6334 IRS1 & 2  & 2     & 50  & 10 &  0.4 &  7 & 10    & 2     & 1 &0.2&0.2& 1 & 0.01 \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
%                 SO   SO2    OCS  CS    H2S  H2CS   NS   HCS+  
Hot cores$^b$  & 4  & 20    & 5   &  8 & 9    & 6 & 80   & ...    &0.2 & 2 & 0.5 & 1 & 0.1 \\
PDRs$^c$       & 9  &0.1    & ... & 20 & 6    &...& ...  & ...    &100 &0.005&0.5&0.3& ...\\ 
Dark clouds$^d$& 20 & 4     & 2   &  1 & 0.8  & 6 & ...  & 0.6    & 5  & 4 & 20 & 0.8 & ... \\
Shocks$^e$     &200 &100    &10   &  4 & 4000 & 8 & ...  & 0.1    & 2  & 25& 50 &1000 & ... \\
Low mass protostars$^f$                                          
               & 4  &0.6    & 7   &  3 & 2    & 4 & ...  & 0.2    & 10 & 0.2& 1 & 0.7 & ... \\
\hline
    \end{tabular}}
\smallskip
\begin{tabular}{ll}
\par
$^a$ From \citet{fvdt00}, except MonR2 IRS3. & $^d$ L134N: \citet{ohishi92}. \\
$^b$ Source average from \citet{jh98sulf} .  & $^e$ Orion Plateau: \cite{sutton95,minh90}. \\
$^c$ Orion Bar: \citet{jansen95} .           & $^f$ IRAS 16293-2422: \cite{fred02}. \\
\end{tabular}
\end{table}