\begin{table}%T4
\caption{\label{tab:hd128898}Mean longitudinal magnetic field for the time series of~HD~128898.}
%\centering
\par
\begin{tabular}{crr|crr}
\hline\hline
MJD &\multicolumn{1}{c}{$\left<{\cal B}_z\right>$}&\multicolumn{1}{c}{$\sigma{}_z$} 
&MJD&\multicolumn{1}{c}{$\left<{\cal B}_z\right>$} &\multicolumn{1}{c}{$\sigma{}_z$}\\
&\multicolumn{1}{c}{[G]}&\multicolumn{1}{c}{[G]} & &\multicolumn{1}{c}{[G]}&\multicolumn{1}{c}{[G]} \\
\hline
52~383.278303 & $-$5 & 60 &	52~383.301002 & $-$306 & 63 \\
52~383.279870 & $-$361 & 60 &	52~383.302584 & $-$1 & 66 \\
52~383.281422 & $-$63 & 63 &	52~383.304163 & $-$195 & 70 \\
52~383.282986 & $-$368 & 63 &	52~383.305740 & $-$385 & 70 \\
52~383.284544 & $-$291 & 63 &	52~383.307315 & $-$287 & 70 \\
52~383.288427 & $-$163 & 60 &	52~383.308895 & $-$342 & 63 \\
52~383.289992 & $-$256 & 63 &	52~383.310474 & $-$233 & 70 \\
52~383.291561 & $-$478 & 63 &	52~383.314201 & $-$230 & 57 \\
52~383.293135 & $-$472 & 63 &	52~383.315821 & $-$148 & 54 \\
52~383.294707 & $-$298 & 60 &	52~383.317441 & $-$251 & 57 \\
52~383.296279 & $-$321 & 63 &	52~383.319067 & $-$23 & 60 \\
52~383.297857 & $-$40 & 63 &	52~383.320686 & $-$310 & 57 \\
52~383.299426 & $-$118 & 63 &	52~383.322304 & $-$271 & 57 \\
\hline
\end{tabular}
\end{table}