\begin{table}
\begin{tabular}{cccr}
\hline
symbol & value & name & ref \\
\hline
$AU~$  & 1.49597870691D8 km & astronomical unit & \\
$R_E~$ & 6378.1366 km &  equatorial radius of the Earth & \\
$a_{M0}$ & 383597.7916 km & averaged Earth--Moon semimajor axis at J2000 &  cdT p. 254 \\
\hline
\end{tabular}
\caption{ COnstants}
\llabel{Tab.const}
\end{table}