\begin{table}%t2
\caption{\label{T2}Fundamental frequencies for the orbital solution $\Sa$  (Table~\ref{T1}).}
%\centering
\small
\begin{tabular}{ccrr}
\hline\hline
      & Frequency   & Period \\
      & $^\circ/{\rm yr}$ & yr \\
 \hline
mean & $n_b$ &   653.645983    &       0.550757\\
motions & $n_c$ &   217.563988    &       1.654686\\
 \hline
secular & $g_1$ &    --0.477010    &    --754.701\\
frequencies & $g_2$ &    --0.009651    &   --37~303.55\\
 \hline
libration frequency & $l_\theta$ & 9.015796    &      39.9299 \\ 
\hline
\end{tabular}
\end{table}