\begin{table}%T4
%\centering
\par
\caption{\label{four_orbits}The orbits for Gliese~22~AC.}
\begin{tabular}{lllll}\hline\hline
Element & Hershey (\cite{Her73}) & Heintz (\cite{Hei93}) &
  S\"oderhjelm (\cite{Sod99}) & This work \\ \hline
$P$ [yr] & 15.95 $\pm$ 0.22 & 16.0 & 15.4 & 16.12 $\pm$ 0.2 \\
$T$      & 1956.0 $\pm$ 2.8 & 1988.9 & 1989.0 & 2000.47 $\pm$ 0.20 \\
$e$    & 0.05 $\pm$ 0.07  & 0.0    & 0.0    & 0.18 $\pm$ 0.03 \\
$a ["]$ & 0.51  & 0.525  & 0.450  & 0.529 $\pm$ 0.005 \\
$i$ [deg] & 45.0  &  42.0  & 27.0 &  46 $\pm$ 1 \\
$\Omega$  & 167.0 & 171.0  & 24.0 & 179.7 $\pm$ 1 \\
$\omega$  & 160.0 & 0.0 & 0.0 & 93.0 $\pm$ 5 \\ 
\hline
\end{tabular}
\end{table}