\begin{table}%t6
\caption{Depth of the H$_{\alpha}$ line of the primary components
of of some short-period RS CVn stars.}\label{tab6}
%\centering
\par
\begin{tabular}{llllllll}
\hline \hline
 Star    & XY UMa& SV Cam & RT And &  BH Vir \\
\hline
$T_{{\rm eff}}$ (K)     &  5780 & 5800   & 6150   &  6100 \\
$d_{{\rm obs}}$&  0.31 & 0.32   & 0.28   &  0.22 \\
\hline
\end{tabular}
\end{table}