\begin{table}%T6
\caption{$\ell=2$ modes for the best fitting model.}\label{tab6}
%\centering
\par
\small
\begin{tabular}{cccc}\hline\hline 
$ k$ & Period (s) & $k$ & Period (s) \\ \hline 1 & 72.0 & 13 & 431.5 \\2 & 142.1 & 14 & 455.2 \\3 & 163.4 & 15 & 474.2 \\4 & 194.3 & 16 & 508.8 \\5 & 224.2 & 17 & 542.1 \\6 & 240.1 & 18 & 559.6 \\7 & 269.3 & 19 & 587.6 \\8 & 300.7 & 20 & 605.0 \\9 & 326.4 & 21 & 633.8 \\10 & 346.2 & 22 & 672.3 \\11 & 374.2 & 23 & 698.6 \\12 & 397.0 & 24 & 712.2 \\   \hline 
\end{tabular}
\end{table}