\begin{table}%t4
%\centering
\par
\caption{Third-body orbital parameters.}
\label{GD}
\begin{tabular}{lcc}
\hline\hline
Parameter & Unit & Value\\
\hline
$P_1$     & day  & 1.8114741\\
$HJD_0$   &      & 2438448.4073\\
$P_2$     & day  & 293.3\\
$JD_{\rm periastron}$&& 2438010\\
$e$       &      & 0.615\\
$a_{1,2}$ & day  & 0.00522\\
$\omega^{0}_{1984.3}$ &deg& 2.7\\
$m_2$     & $M_{\odot}$& 14.2\\
$rms$ of an O--C&day& 0.00079\\
\hline
\end{tabular}
\end{table}