\begin{table}%t2
  \caption{\label{T2}The stellar sample. II. Ca index measurements.}
  %\centering
\par
\small
  \begin{tabular}{lrlc}
  \hline\hline
  Star & Rot. per.   &  Sp. type & \multicolumn{1}{c}{Time-base} \\
       & (days)      &          & \multicolumn{1}{c}{(years)} \\
  \hline
HD 131156A = $\xi$ Boo A &  6.25  & G8V    & 35 \\	
HD 131156B = $\xi$ Boo B & 11.1  & K4Ve   & 35 \\
HD 100180 = 88 Leo & 14.3  & G0V    & 34 \\
HD 201092 = 61 Cyg B & 35.5   & K7V    & 35 \\
HD 201091 = 61 Cyg A & 36.1   & K5V    & 35 \\
HD 95735 = GJ 411 & 54.7   & M2V    & 34 \\
  \hline
  \end{tabular}
\end{table}