\begin{table}%t2 {%\centering \par \caption{\label{tab:xrayparams}X-ray parameters of the Z~CMa binary and its jet.} \begin{tabular}{lcrrrr} \hline\hline\\[-3.2mm] \multicolumn{1}{c}{Date} & \multicolumn{1}{c}{Opt/IR} & \multicolumn{1}{c}{Offax} & \multicolumn{1}{c}{Counts} & \multicolumn{1}{c}{Expo$^*$} & \multicolumn{1}{c}{$P_{\rm KS}$} \\ & & \multicolumn{1}{c}{[$^\prime$]} & \multicolumn{1}{c}{in $0.3{-}8$~keV} & \multicolumn{1}{c}{[s]} & \\ \hline Dec. 2003 & Z~CMa & $ 1.95 $ & $ 47.6 \pm 6.9$ & $ 17857.$ & $ 0.54$ \\ Dec. 2003 & jet & $ 1.91 $ & $ {<}9.4$ & $ 17857.$ & $ - $ \\ \hline Dec. 2008 & Z~CMa & $ 0.30 $ & $ 107.2 \pm 10.4$ & $ 39594.$ & $ 0.50$ \\ Dec. 2008 & jet & $ 0.34 $ & $ 20.7 \pm 4.6$ & $ 39610.$ & $ 0.32$ \\ \hline \end{tabular}} \par \medskip{$^*$ The effective exposure time in the 2003 Dec. observation is substantially reduced with respect to the duration of the observation because the star is near a chip border.} \end{table}