\begin{table}%T1
\caption{Clump centre positions$^1$.}\label{tab1}
%\begin{center}
{
\begin{tabular*}{8cm}{*{4}{l}}
\noalign{\smallskip}
\hline\hline
\noalign{\smallskip}
Model        & Clump A & Clump B & Position angle\\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
1            &  $(0,-1)$  & $(0,1)$ & $0^\circ$  \\
2            &  $(-1,0)$  & $(1,0)$ & $90^\circ$ \\
3            &  $(-1,-0.5)$ & $(1,0.5)$ & $63^\circ$ \\
4            &  $(-1.5,-0.5)$ & $(1.5,0.5)$ & $72^\circ$ \\
\noalign{\smallskip}
\hline
\end{tabular*}}
\smallskip{
$^1$ In units of $10^{16}$~cm.}
%\end{center}
\par
\end{table}