\begin{table}%t2
   %\centering
\par
   \caption{Scaling output for a planet like $\tau$~Bootes at different stellar system 
   ages (4.6~Gyr, 1.0~Gyr and 0.7~Gyr). See text for details.
   \label{tab_time}}  
\par
   \begin{tabular}{lccc}\hline\hline
        $\tau$~Bootes 
		& 4.6~Gyr & 1.0~Gyr & 0.7~Gyr \\[4pt] %\hline
        \hline
	$v(t)$ (stellar wind velocity) [km~s$^{-1}$]
		& 400
		& 731
		& 840\\[4pt] %\hline
	$n_0(t)$ (stellar wind density at 1~AU) [m$^{-3}$]
		& $1.0\times 10^{7}$
		& $9.5\times 10^{7}$
		& $15.9\times 10^{7}$\\[4pt] 	
	\hline
        $\mathcal{M}$ (magnetic moment) [$\mathcal{M}_{\rm J}$]
		& $0.5\ldots2.7$ 
		& $0.5\ldots2.7$ 
		& $0.5\ldots2.7$ \\[4pt] %\hline
	$P_{{\rm rad}}$ (emitted radio power) [W]
		& $0.69\times 10^{14}\ldots2.1\times 10^{14}$ 
		& $1.3\times 10^{15}\ldots3.8\times 10^{15}$ 
		& $2.5\times 10^{15}\ldots7.3\times 10^{15}$ \\[4pt] %\hline
	$\Phi_{{\rm  AU}}$ (flux density at 1~AU) [Jy]
		& $4.0\times 10^{10}\ldots9.7\times 10^{10}$ 
		& $7.4\times 10^{11}\ldots1.8\times 10^{12}$ 
		& $1.4\times 10^{12}\ldots3.5\times 10^{12}$  \\[4pt] %\hline
	$\Phi_s$ (flux density at distance $s$) [Jy] 
		& $0.0039\ldots0.0094$ 
		& $0.071\ldots0.17$ 
		& $0.14\ldots0.33$  \\[4pt] %\hline
     	$f_{\rm c}^{\max}$ (maximum frequency) [MHz]
		& $6.7\ldots19$ 
		& $6.7\ldots19$ 
		& $6.7\ldots19$ \\[4pt] \hline
   \end{tabular}
   \end{table}