\begin{table}%t2
 \caption{\label{tab:table2} Periods associated with the unstable
and stable eigenvalues (minutes) for $B_{00}=100$~G.}
 \small%\centering
\par
\begin{tabular}{cccccccccccc}
\hline\hline
 $P_{1}$&$
P_{2}$&$P_{3}$&$P_{4}$&$P_{5}$&$P_{6}$&$P_{7}$&$P_{8}$&$P_{9}$&$P_{10}$&$P_{11}$&$P_{12}$
\\ \hline
$36.3 \ i$&$0.7 \ i$&$0.5 \ i$&$0.36$&$0.33 $&$0.2 $&$0.15 $&$0.14
$&$0.1 $&$0.0$&$0.0$&$0.0$\\ 
\hline
\end{tabular}
\end{table}