\begin{table}%T2
\caption{Summary of the results obtained in the case where the angular
         separation of the two stars is $\frac{1}{2}\lambda/D$. The quantities
         $\Delta m_0$, $\Delta \Theta_{\rm r} $, and $\Delta m_{\rm r}$ are defined in 
         the text.
         \label{tab:2}}
%\centering
\par
\begin{tabular}{c|lll|lll|lll} 
\hline\hline
main star & \multicolumn{3}{c|}{case \textbf{A}}
         & \multicolumn{3}{c|}{case \textbf{B}}
         & \multicolumn{3}{c}{case \textbf{C}}            \\
$K$-band mag.& $\Delta m_0$ & $\Delta \Theta_{\rm r}$ & $\Delta m_{\rm r}$
         & $\Delta m_0$ & $\Delta \Theta_{\rm r}$ & $\Delta m_{\rm r}$
         & $\Delta m_0$ & $\Delta \Theta_{\rm r}$ & $\Delta m_{\rm r}$ \\ \hline
  10     & 3.5          & 20\%              & 3.75        
         & 3            & 20\%              & 2.8  
         & 2.5          & 20\%              & 2.4          \\ %\hline
  12     & 3            & 10\%              & 3.2         
         & 2.5          & 20\%              & 2.5
         & 2.5          & 15\%              & 3.3          \\ %\hline
  14     & 2.5          & 20\%              & 2.5         
         & 2.5          & 20\%              & 2.2 
         & 2.5          & 15\%              & 3.1          \\ %\hline
  15     & 2.5          & 20\%              & 2
         & 2            & 10\%              & 1.5 
         & 2            & 20\%              & 2.7          \\ %\hline
  17     & 2            & 20\%              & 1           
         & 1            & 20\%              & 0.4
         & 1            & 10\%              & 0.4          \\ \hline
\end{tabular}
\end{table}