\begin{table}%t1
\caption{\label{tab1}$M_2$ for $P_h$ = 1.829 and $P_h$~= 3.439  from  various $M_2-P$~relations or   different $\alpha$ and $\beta$~values in the literature (see text).}
%\centering
\small
\begin{tabular}{lcc}
\hline \hline
 &$P_h$ = 1.829  &    $P_h$ = 3.439  \\  
\hline                                                                            
Patterson et~al.   & 0.134 &  0.234\\                                                                Smith \& Dhillon  &  0.100 &  0.267 \\                                                               Knigge   &  0.140 &  0.236\\                                                                         Warner   &  0.138 &  0.304 \\                                                                        Equation (7) &     0.121 &  0.227 \\                                                                 \hline
\end{tabular}
\end{table}