\begin{table}%t2
\caption{Parameters of the programme stars. \label{parameters}}
\small%\centering
$$
\begin{tabular}{lr@{~$\pm $~}lr@{~$\pm $~}lr@{~$\pm $~}lr@{~$\pm $~}lr@{~$\pm $~}lr@{~$\pm $~}l}
\hline\hline
\noalign{\smallskip}
                 & \multicolumn{2}{c}{$\tau$~Sco}   &
\multicolumn{2}{c}{HR~3055}   & \multicolumn{2}{c}{HR~1861}   &
\multicolumn{2}{c}{HR~2928}   & \multicolumn{2}{c}{HR~3468} & \multicolumn{2}{c}{HR~5285}\\
\hline
$T_{\rm eff}$~(K)      &32~000 & 300&31~200 & 300&27~000 & 400&
26~300 & 400& 22~900 & 400&21~500 & 400\\
$\log g$~(cgs)     &4.30 & 0.05&3.95 & 0.05&4.12 & 0.05& 4.15 & 0.05&3.60 & 0.05&4.20 & 0.05\\
$\xi$~(km~s$^{-1}$)   &5 & 1      &  8 & 1    & 3 & 1     & 3 & 1   & 5 & 1 & 4 & 1\\
$v\sin i$~(km~s$^{-1}$)& 4 & 2  &  29 & 4   & 12 & 1    & 14 &  1  & 11 & 3 &18 & 1\\
$\zeta$~(km~s$^{-1}$) & 4 & 2    &  37 & 8   & \multicolumn{2}{c}{\ldots}  &
20 &  2   & 20 & 2 & \multicolumn{2}{c}{\ldots}\\
$y$ (by number) &  0.089 & 0.01 & 0.080 & 0.01  &
0.089 & 0.01  &  0.089 & 0.01  & 0.089 & 0.01   & 0.089 & 0.01\\
\hline
\end{tabular}
$$
\end{table}