\begin{table}%T4
\caption{Summary of the results obtained in the case where the angular
         separation of the two stars is $\frac{1}{2}\lambda/B$, where
         $B$ is the maximum baseline of LBT.
         \label{tab:4}}
%\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   & 5            & 20\%              & 3.5        
         & 3.5          & 20\%              & 2  
         & 3            & 22\%              & 2.5          \\ %\hline
    12   & 4            & 10\%              & 2.8
         & 3            & 20\%              & 2 
         & 3            & 22\%              & 2.5          \\ %\hline
    14   & 3.5          & 10\%              & 2.5
         & 3            & 20\%              & 1.8 
         & 2.5          & 22\%              & 2.3          \\ %\hline
    15   & 3            & 10\%              & 2.3
         & 2.5          & 10\%              & 1.7 
         & 2.5          & 22\%              & 2            \\ %\hline
    17   & 2.5          & 10\%              & 1.7
         & 2            &  0\%              & 1.4
         & 1.5          & 10\%              & 1            \\ \hline
\end{tabular}
\end{table}