\begin{table}%t7
%\centering
\par
\caption{Orbital elements of two Am stars.
\label{orbam}}
\par
\begin{tabular}{lrlrl}
\hline\hline%\noalign{\smallskip}
No. & \multicolumn{2}{c}{Tr 144} & \multicolumn{2}{c}{Tr 145}  \\
\hline%\noalign{\smallskip}
$P$ [d]               & 11&787023 & 68&252  \\
                    &  0&000034 &  0&022  \\
$T$ [HJD]             & 49987&406 & 49967&7 \\
                    &     0&006 &     1&3 \\
$V_{\rm o}$ [km~s$^{-1}$] & --0&36     & +0&05   \\
                    &  0&10     &  0&44   \\
e                   &  0&0349   &  0&287  \\
                    &  0&0034   &  0&037  \\
$\omega$ [$\degr$]  &  155&1    &  262&9  \\
                    &    5&6    &    7&6  \\
K [km~s$^{-1}$]     &  40&61    &  13&54  \\
                    &   0&14    &   0&39  \\
$f(m)$                &  0&08185  & 0&0154  \\
                    &  0&00087  & 0&0013  \\
$a\sin i$ [Gm]          &   6&579   &  12&17  \\
                    &   0&023   &   0&35  \\
$\sigma$(O--C) [km s$^{-1}$] & 0&47 &  1&12  \\
$n_{\rm obs}$             & \multicolumn{2}{c}{28}  & \multicolumn{2}{c}{17} \\
\hline
\end{tabular}
\end{table}