\begin{table}%t1
\caption{Main parameters of observed active stars.}
\label{tab:targets}
%\centerline
{
\begin{tabular}{lccc}
\hline
\hline
Parameter & HK~Lac & IM~Peg & VY~Ari \\
\hline
HD           & 209813  & 216489   & 17433 \\  
Sp. type     & K0III   & K2III-II & K3-4V-IV \\ 
$v\sin i$ (km~s$^{-1}$)    & 23.0$^{a}$   &  25.6$^{b}$   &   8.6$^{c}$ \\
$P_{\rm rot}$ (days) & 24.4284$^{d}$ & 24.4936$^{e}$ & 16.1996$^{e}$ \\
$T_{\rm max}$ (K) & 4765$^{f}$ & 4666$^{f}$ & 4916$^{f}$ \\ 
$V_{\rm max}$ (mag) & 6.66$^{h}$ & 5.55$^{i}$ & 6.69$^{l}$ \\ 
$V_{\rm ph}$ (mag) & 6.73$^{f}$ & 5.72$^{f}$ & 6.84$^{f}$ \\ 
\hline
\multicolumn{4}{c}{Ephemerids}\\
\hline
HJD0 & 2~440~017.17$^{g}$ & 2~443~734.0$^{e}$ & 2~451~856.0$^{f}$ \\
$P_{\rm phot}$ (days) & 24.283$^{f}$ & 24.789$^{f}$ & 16.292$^{f}$ \\
\hline
\end{tabular}}
\medskip
$^{a}$ Randich et~al. (\cite{Rand94}).  \\
$^{b}$ De Medeiros \& Mayor (\cite{DeMe99}). \\
$^{c}$ Bopp et~al. (\cite{Bopp89}). \\
$^{d}$ Orbital period  (Gorza \& Heard \cite{Gorza71}).\\
$^{e}$ Strassmeier et~al. (\cite{Stra97}).\\
$^{f}$ Present work. \\
$^{g}$ Strassmeier et~al. (CABS \cite{Stra93}). \\
$^{h}$ Ol\'ah et~al. (\cite{Olah97}). \\
$^{i}$ Berdyugina et~al. (\cite{Berdy99}). \\
$^{l}$ Strassmeier \& Bopp (\cite{Stra92}).
\end{table}