\begin{table} %t5
\caption{\label{tab_cd}Column densities -- OCS. }
\small%\centering
\par
\begin{tabular}{lllll}
\hline 
\hline \noalign{\smallskip}
 Species & Extended ridge & Compact ridge & Plateau & Hot core \\
 & $N \times 10^{15}$ (cm$^{-2}$) & $N$ $\times$ 10$^{15}$ (cm$^{-2}$) &
$N \times 10^{15}$ (cm$^{-2}$) & $N$ $\times$ 10$^{15}$ (cm$^{-2}$)\\
\hline
OCS & 2.0~$\pm$~0.5 & 3.0~$\pm$~0.8 & 7.5~$\pm$~1.9 & 15~$\pm$~4 \\
OCS assuming $^{32}$S/$^{34}$S~=~20 & 2.0~$\pm$~0.5 & 14~$\pm$~4 &
10~$\pm$~3 & 60~$\pm$~15 \\
OCS assuming $^{12}$C/$^{13}$C~=~45 & 2.7~$\pm$~0.5 & 18~$\pm$~4 &
13.5~$\pm$~3 & 45~$\pm$~9 \\
OCS (average) & 2.4~$\pm$~0.5 & 16~$\pm$~4 &
11.8~$\pm$~3 & 53~$\pm$~10 \\ 
OC$^{34}$S & 0.15~$\pm$~0.03 & 0.70~$\pm$~0.18 &
0.50~$\pm$~0.13 & 3.0~$\pm$~0.8 \\
OC$^{33}$S & 0.050~$\pm$~0.025 & 0.090~$\pm$~0.045 &
0.10~$\pm$~0.05 & 0.30~$\pm$~0.15 \\
O$^{13}$CS & 0.060~$\pm$~0.015 & 0.40~$\pm$~0.10 & 0.30~$\pm$~0.08 & 1.0~$\pm$~0.3 \\
$^{18}$OCS & 0.010~$\pm$~0.005 & 0.070~$\pm$~0.035 & 0.030~$\pm$~0.015 & 0.10~$\pm$~0.05 \\
O$^{13}$C$^{34}$S & $\la$0.010 & $\la$0.050
&$\la$0.050 & $\la$0.070 \\
$^{17}$OCS & $\la$0.005
&$\la$0.020 & $\la$0.010 & $\la$0.020 \\
OC$^{36}$S & $\la$0.005 & $\la$0.030 &
$\la$0.020 & $\la$0.030 \\
OCS $\nu_2$ = 1 & ... & ... & ... & 1.5~$\pm$~0.4 \\
OCS $\nu_3$ = 1 & ... & ... & ... & 0.15~$\pm$~0.07 \\
\noalign{\smallskip}
\hline 
\end{tabular}
\tablefoot{Column densities for the different OCS isotopologues and OCS
vibrationally excited derived from our model of the different Orion's
components (see text, Sect.~\ref{sect_col_ocs}).}
\end{table}