\begin{table}%t1
\par
\caption{\label{table1}The sample with the 3~different chromospheric indices.}
\begin{tabular}{c c c c c}
\hline\hline
Star&$T_{\rm eff}$&1--{\AA}  K &$F^{\prime}_ {\rm K}$& $\log R^\prime_{\rm K}$\\
    &        &index       & [10$^6$~erg/ &                   \\
    &[K]     &      [m\AA]&  cm$^2$~s]             & [dex]             \\
\hline
\multicolumn{4}{c}{Hyades, 0.7 Gyr}\\                    
 van Bueren   1 & 6250 &180 & 1.95 $\pm$ 0.17  &--4.65  $\pm$ 0.04\\
 van Bueren   2 & 6050 &223 & 2.18 $\pm$ 0.24  &--4.54  $\pm$ 0.05\\
 van Bueren  10 & 6100 &281 & 3.00 $\pm$ 0.31  &--4.42  $\pm$ 0.04\\
 van Bueren  15 & 5750 &308 & 2.30 $\pm$ 0.34  &--4.43  $\pm$ 0.06\\
 van Bueren  17 & 5650 &272 & 1.73 $\pm$ 0.29  &--4.53  $\pm$ 0.07\\
 van Bueren  18 & 5900 &294 & 2.60 $\pm$ 0.33  &--4.42  $\pm$ 0.05\\
 van Bueren  31 & 6200 &261 & 3.01 $\pm$ 0.28  &--4.44  $\pm$ 0.04\\
 van Bueren  49 & 6050 &207 & 1.95 $\pm$ 0.21  &--4.59  $\pm$ 0.05\\
 van Bueren  52 & 6050 &248 & 2.46 $\pm$ 0.27  &--4.49  $\pm$ 0.05\\
 van Bueren  65 & 6250 &202 & 2.25 $\pm$ 0.20  &--4.58  $\pm$ 0.04\\
 van Bueren  66 & 6250 &253 & 3.01 $\pm$ 0.27  &--4.46  $\pm$ 0.04\\
 van Bueren  73 & 6000 &270 & 2.61 $\pm$ 0.30  &--4.45  $\pm$ 0.05\\
 van Bueren  88 & 6250 &228 & 2.63 $\pm$ 0.23  &--4.52  $\pm$ 0.04\\
 van Bueren  97 & 5900 &279 & 2.44 $\pm$ 0.31  &--4.45  $\pm$ 0.05\\
 van Bueren 118 & 6100 &161 & 1.46 $\pm$ 0.15  &--4.73  $\pm$ 0.04\\
\hline
\multicolumn{4}{c}{Praesepe, 0.7 Gyr} \\                    
 KW  49         &6150 &233  & 2.39  $\pm$ 0.25 & --4.53  $\pm$ 0.04\\
 KW 100         &6150 &255  & 2.71  $\pm$ 0.28 & --4.48  $\pm$ 0.04\\
 KW 208         &6280 &238  & 2.74  $\pm$ 0.25 & --4.51  $\pm$ 0.04\\
 KW 326         &5800 &234  & 1.67  $\pm$ 0.25 & --4.59  $\pm$ 0.06\\
 KW 368         &5720 &270  & 1.78  $\pm$ 0.29 & --4.53  $\pm$ 0.07\\
 KW 392         &6250 &248  & 2.84  $\pm$ 0.26 & --4.48  $\pm$ 0.04\\
 KW 418         &6150 &239  & 2.48  $\pm$ 0.26 & --4.51  $\pm$ 0.04\\
\hline
\multicolumn{4}{c}{NGC 3680, 1.4 Gyr}\\        
\par
Eggen 60        &6010 & 95 $\pm$  5  & 0.56 $\pm$ 0.09& --5.12 $\pm$ 0.07\\
Eggen 70        &6210 & 84 $\pm$ 10  & 0.47 $\pm$ 0.16& --5.25 $\pm$ 0.14\\
\hline
\multicolumn{4}{c}{IC 4651, 1.7 Gyr}\\  
\par
AMC 1109 &6060 &$102\pm 10$ & 0.65 $\pm$ 0.14  &  --5.07 $\pm$ 0.10\\
AMC 2207 &6050 & $85\pm 10$ & 0.46 $\pm$ 0.13  &  --5.22 $\pm$ 0.13\\
AMC 4220 &5910 &$133\pm 20$ & 0.91 $\pm$ 0.24  &  --4.88 $\pm$ 0.12\\
AMC 4226 &5980 & $93\pm 15$ & 0.52 $\pm$ 0.18  &  --5.15 $\pm$ 0.15\\
Eggen 45 &6320 & $74\pm 10$ & 0.38 $\pm$ 0.16  &  --5.38 $\pm$ 0.18\\
\hline
\multicolumn{4}{c}{M 67, 4.3 Gyr} \\ 
\par
Sanders  746 & 5750 &108 $\pm$ 20 & 0.56 $\pm$ 0.20 & --5.05 $\pm$ 0.16 \\
Sanders 1048 & 5900 & 85 $\pm$ 10 & 0.40 $\pm$ 0.12 & --5.24 $\pm$ 0.13 \\
Sanders 1092 & 6160 & 88 $\pm$ 15 & 0.54 $\pm$ 0.22 & --5.18 $\pm$ 0.17 \\
Sanders 1255 & 5840 &105 $\pm$ 20 & 0.57 $\pm$ 0.22 & --5.06 $\pm$ 0.17 \\
Sanders 1283 & 6100 & 82 $\pm$ 15 & 0.43 $\pm$ 0.21 & --5.26 $\pm$ 0.21 \\
Sanders 1287 & 6100 & 90 $\pm$ 10 & 0.50 $\pm$ 0.14 & --5.19 $\pm$ 0.12 \\
\hline                    
\multicolumn{4}{c}{NGC 5822, 1.2 Gyr}   \\                           
  TATM 11003& 6160 &197~$\pm$~8&2.02 $\pm$ 0.22&--4.61~$\pm$~0.05\\
 TATM 11014& 6270 &217~$\pm$~7&2.52 $\pm$ 0.24&--4.54~$\pm$~0.04\\
\hline
\multicolumn{4}{c}{IC 4756, 0.8 Gyr}   \\                            
    HER 165& 6070 &211~$\pm$~7&2.12~$\pm$~0.23&-4.56~$\pm$~0.05\\
    HER 240& 6010 &206~$\pm$~6&1.91~$\pm$~0.22&-4.59~$\pm$~0.05\\
     HER 97& 6120 &190~$\pm$~9&1.91~$\pm$~0.22&-4.62~$\pm$~0.05\\
\hline                    
\multicolumn{4}{c}{Solar cycle 21, from \cite{wl81} }   \\       
Sun &5780&$95\pm 10$& 0.45~$\pm$~0.10\\
\hline
\end{tabular}
\end{table}