\begin{table}%t1
\caption{\label{table:assoc}Properties of the associations studied in this paper.}
%\centering
\small
\begin{tabular}{lrrrr}
\hline\hline \noalign{\smallskip}
Association & $N$ & $n$  & distance & Age\\
\hline
$\epsilon$~Chamaleontis ($\epsilon$ChA)&23 &0& 93--123  &~~~6\\
TW~Hydrae (TWA)     & 22 &0& 28--73  & ~~~8\\  
$\beta$~Pictoris ($\beta$PA) &48&2& 10--80&10\\
Octans (OctA)         & 15 &0& 82--175 &20?\\
Tucana-Horologium (THA)     &45 &1& 37--78   &30\\
Columba (ColA)        &44 &0& 35--150 &30\\
Carina (CarA)        & 23 &1& 45--160 &30\\
Argus (ArgA)       & 64 &1& 29--164&40\\  
AB~Doradus (ABDA)     & 92 &4& 7--143 &70\\
\hline    
\end{tabular}  
\end{table}