\begin{table}%t2
\caption{\label{table_params}$J$ values associated with each discriminant parameter, and for the variable $F$ obtained by linear
combination of the three parameters.}
%\centerline
 {\small \begin{tabular}{c c c c c c}
\hline\hline
& \vline & $\log$($\textit{A}$) & $\log$($\Delta$) & log($\nabla$) & $F$(3D)\\  
\hline    
   $J$ & \vline & 3.17 & 4.71 & 1.8 & 6.27 \\
\hline   
   $a$ & \vline & 0.27 & 0.59 & 0.14 &  ...    \\ 
\hline
\end{tabular}}
\smallskip
The $a$'s are the coefficients of the linear combination (absolute values).
\end{table}