\begin{table}
%\begin{center}
\par
\caption{Results of the collision between $\mu$~ring particles and
the close satellites (Mab and Puck) after $1000$~years.}
\label{T-mu}
\begin{tabular}{lcccccc} \hline\hline
Particle size & \multicolumn{3}{c}{Puck} & \multicolumn{3}{c}{Mab}\\
\cline{2-4}\cline{5-7}\\[-3mm] ($\mu$m) & $N_\%$ & $\overline{T}$ (years)
& $\overline{v}$ (m~s$^{-1}$)& $N_\%$ & $\overline{T}$ (years) &
$\overline{v}$ (m~s$^{-1}$) \\ 
\hline
1 & 60 & 154 & 468 & 2 & 443 & 718 \\
3 & 17 & 113 & 182 & 3 & 474 & 379 \\
5 & 12 & 151 & 162 & 3 & 445 & 354 \\
10 & 9 & 189 & 158 & 3 & 454 & 344 \\
\hline
\end{tabular}
%\end{center}
\par
\end{table}