\begin{table}%t7
\caption{\label{tab:orboverview}The orbital elements of the programme stars.}
\par
%\centering
\small
\begin{tabular}{lllllllllllll} 
\hline\hline 
 & \multicolumn{2}{c}{IRAS~08544} &  \multicolumn{2}{c}{IRAS~12222} &  
\multicolumn{2}{c}{EN~Tra} & \multicolumn{2}{c}{IRAS~15469} &  
\multicolumn{2}{c}{IRAS~19125} &  \multicolumn{2}{c}{IRAS~19157} \\
 & & $\sigma$ & & $\sigma$ & & $\sigma$ & & $\sigma$ & & $\sigma$ & &
 $\sigma$ \\ 
 \hline
Period (days) & 507.8  & 1.5 & 913.8  & 4.3 &
1493.  & 7. & 389.9     & 0.5  & 519.6  & 2   & 119.5   & 0.2\\
$K$ (\kms)                           & 8.6    & 0.3 & 3.5    & 0.5 &
16.3  & 0.6 & 11.9      & 0.3  & 12.6    & 0.5 & 7.3     & 0.7\\
$e$                                  & 0.24   & 0.02 & 0.00   & 0.0 &
0.32 & 0.04 &0.09       & 0.02 & 0.25    & 0.03 & 0.31   & 0.07\\
$\omega$ ($^{\circ}$)               & 47.   & 7.    &        &     &
160. & 6.  & 133.      & 16.  & 242.     & 6.  & 80.     & 14. \\
$T_{0}$ (periastron) (JD24+)       & 51482. & 10.  &       &     &
538535. & 22. & 51491.     & 17   & 53061. & 8.  & 51849.  & 5. \\
$\gamma$ (\kms)                    & 61.98   & 0.16 & 3.65   & 0.17
&$-$7.1 & 0.4 & $-$14.9   & 0.2  & 67.0 & 0.3 & 33.1  & 0.3 \\
rms  (\kms)                     & 1.88   &     & 1.47   &     & 2.42 && 2.1 &  &
 1.98 &     & 3.31   &\\  
$a_1 \sin i$ (AU)                  & 0.39   & 0.01 & 0.29 & 0.04    &
2.12 & 0.08  & 0.42      &   0.01   & 0.58  &  0.02  & 0.08  & 0.01 \\
$F(M)$ ($M_{\odot}$)                  & 0.0304   &  0.0033   &   0.0042
&  0.0017   & 0.57 & 0.06 & 0.068    & 0.006     & 0.097 &  0.012   &
0.0041 & 0.0012 \\
$N$                                  & 161    &     & 82     &     & 63
& & 161        &      & 90   &     & 111     &  \\ 
$\Delta t$ (cycles)                & 6.6     &     & 9.2    &     &3.8
&& 8.7        &      & 5.9  &     & 28.4    &\\
$\Delta m(V)$                      & 0.25   &     & 0.23       &     & 0.81
& & 0.25       &      & 0.19 &     & 0.23   & \\ 
\hline
\end{tabular}
\end{table}