\begin{table}%t9
\caption{Equivalent widths and derived line abundances for the set of \ion{O}{ii}~lines used in our analysis. Line abundances refer to the microturbulence given in brackets for each star~($\xi_t$ in~\kms). Uncertainties in the line abundances come from the propagation of the uncertainties of the equivalent width measurements (see text). Some of the \ion{O}{ii}~lines of the Orion~stars
have not been used, as they appear blended. \ion{O}{ii}~$\lambda\lambda$~4072, 4076, and 4078~lines were ruled out in the analysis of~$\tau$~Sco due to the poor quality of the {\sc caspec}~spectrum in this region. Final oxygen abundances for each star were calculated through a~weighted mean of the linear values. Errors represent the statistical deviation for these mean values.}
\label{t_O_EW}
%\centering
\par
\begin{tabular}{c r c l r c l r c l r c l}    
\hline
\hline
Line & \ew$_{\rm o}$ & $\epsilon$(O)$^a$ & $\Delta\epsilon$(O) &
     \ew$_{\rm o}$ & $\epsilon$(O) & $\Delta\epsilon$(O) &
     \ew$_{\rm o}$ & $\epsilon$(O) & $\Delta\epsilon$(O) &
     \ew$_{\rm o}$ & $\epsilon$(O) & $\Delta\epsilon$(O) \\
\hline
 & \multicolumn{3}{c}{HD~149438 ($\xi_t$ = 8.7)} 
 & \multicolumn{3}{c}{HD~37020  ($\xi_t$ = 6.5)} 
 & \multicolumn{3}{c}{HD~37023  ($\xi_t$ = 7.4)} 
 & \multicolumn{3}{c}{HD~37042  ($\xi_t$ = 5.5)} \\
\cline{2-13}
 & \multicolumn{3}{c}{\Teff~= 32~000 K ~~~ \grav~= 4.0} &
  \multicolumn{3}{c}{\Teff~= 30~000 K ~~~ \grav~= 4.0} &
  \multicolumn{3}{c}{\Teff~= 32~000 K ~~~ \grav~= 4.2} &
  \multicolumn{3}{c}{\Teff~= 29~000 K ~~~ \grav~= 4.2} \\
\cline{1-13}
\ion{O}{ii}~4638 &  85 & 8.75 & 0.04 
                             &  -- & -- & --
	     &  -- & -- & --
	     &  -- & -- & --\\
\ion{O}{ii}~4641 & 127 & 8.65 & 0.04
                             & -- & -- & --
		 & -- & -- & --
		 & -- & -- & -- \\
\ion{O}{ii}~4661 &  90 & 8.70 & 0.04
                             &  80 & -- & --
	 &  76 & 8.60 & 0.06
	 &  88 & 8.56 & 0.06 \\
\ion{O}{ii}~4676 &  79 & 8.71 & 0.05
                             &  82 & 8.59 & 0.06
	 &  65 & 8.59 & 0.06
	 &  82 & 8.63 & 0.06 \\
\ion{O}{ii}~4317 &  92 & 8.69 & 0.03
                             & 107 & 8.67 & 0.04
	 &  78 & 8.59 & 0.05
	 &  98 & 8.60 & 0.07 \\
\ion{O}{ii}~4319 &  86 & 8.71 & 0.04
                             & 100 & 8.69 & 0.05
	 &  75 & 8.63 & 0.05
	 &  95 & 8.66 & 0.07 \\
\ion{O}{ii}~4366 &  80 & 8.61 & 0.04
                             &  96 & 8.62 & 0.05
	 &  77 & 8.62 & 0.05
	 & 103 & 8.62 & 0.08 \\
\ion{O}{ii}~4416 & 100 & 8.62 & 0.04
                             & 120 & 8.65 & 0.05
	 &  93 & 8.62 & 0.05
	 & 117 & 8.70 & 0.11 \\
\ion{O}{ii}~4452 &  37 & 8.67 & 0.07
                             &  48 & 8.64 & 0.07
	 &  32 & 8.58 & 0.09
	 &  60 & 8.67 & 0.10 \\
\ion{O}{ii}~4072 &  -- & -- & --
                             & 118 & 8.61 & 0.12
	 &  99 & 8.57 & 0.09
	 & 119 & 8.71 & 0.10 \\
\ion{O}{ii}~4076 &  -- & -- & --
                             & 133 & 8.59 & 0.12
	 & 114 & 8.57 & 0.09
	 & -- & -- & -- \\
\ion{O}{ii}~4078 &  -- & -- & --
                             &  46 & 8.67 & 0.17
	 &  33 & 8.59 & 0.09
	 &  48 & 8.68 & 0.10 \\				\ion{O}{ii}~4941 &  38 & 8.64 & 0.06
                             &  50 & 8.68 & 0.07
	 &  35 & 8.60 & 0.09
	 &  43 & 8.60 & 0.08 \\
\ion{O}{ii}~4943 &  60 & 8.62 & 0.04
                             &  67 & 8.58 & 0.06
	 &  55 & 8.59 & 0.07
	 &  56 & 8.48 & 0.07 \\
\ion{O}{ii}~4956 &  17 & 8.73 & 0.12
                             &  20 & 8.67 & 0.14
	 &  13 & 8.58 & 0.20
	 &  22 & 8.71 & 0.13 \\
\ion{O}{ii}~4891 &  24 & 8.75 & 0.10
                             &  27 & 8.68 & 0.11
	 &  18 & 8.59 & 0.15
	 &  27 & 8.65 & 0.12 \\
\ion{O}{ii}~4906 &  34 & 8.64 & 0.07
                             &  42 & 8.63 & 0.08
	 &  31 & 8.59 & 0.10
	 &  47 & 8.72 & 0.08\\
\hline
 & \multicolumn{3}{c}{$\epsilon$(O) = 8.70 $\pm$ 0.10} &
   \multicolumn{3}{c}{$\epsilon$(O) = 8.65 $\pm$ 0.10} &
   \multicolumn{3}{c}{$\epsilon$(O) = 8.59 $\pm$ 0.10} &
   \multicolumn{3}{c}{$\epsilon$(O) = 8.64 $\pm$ 0.10} \\
\hline
\noalign{\smallskip}
\multicolumn{3}{l}{$^a$ $\epsilon$(O) = log~(O/H) + 12.} & & & & & & & & & & \\
\end{tabular}
\end{table}