\begin{table}%t3
\caption{\label{tab3}Comparison of published global parameters for different F~stars.}
%\centering
\small
\begin{tabular}{c c c c c c} 
\hline\hline
 Stars       & HD 181906 & HD 49933 & HD 181420 & HD 175726 & Procyon   \\ 
               &   this paper & Appourchaux et~al. (2008) & Barban et~al. (2009) & Mosser et~al. (2009b)  & Arentoft et~al. (2008)\\ 
\hline
 Spectral type & F8     &  F5     &  F2       & F9/G0    &  F5  \\
 $T_{\rm eff}$         &  $6300 \pm 150$~K &  6780 $\pm$ 130 K  &  6580 $\pm$ 105 K   & 6000 $\pm$ 100 K  &  6514 $\pm$ 27 K\\
   $[\element{Fe}/\element{H}]$ & $-0.11 \pm 0.14$ dex& $- 0.37$ dex & 0.00 $\pm$ 0.06 dex & $- 0.22\pm 0.1$ dex &  $-0.05$  dex   \\
 $v \sin i$   &  $10 \pm 1~{\rm km~s^{-1}}$ &    $9.5-10.9 ~{\rm km~s^{-1}}$ & $18 \pm 1~{\rm km~s^{-1}}$ &  $13.5 \pm 0.5~{\rm km~s^{-1}}$ & $3.16  \pm 0.5~{\rm km~s^{-1}}$ \\
 $\Delta\nu$ & 87.5 $\pm$ 2.6 $\mu$Hz & 85.9 $\pm$ 0.15 $\mu$Hz & $\sim$75  $\mu$Hz  & $\sim$97$\mu$Hz  & $\sim$55  $\mu$Hz  \\ 
 $\nu_{\rm max}$ & 1900  $\mu$Hz & 1760 $\mu$Hz & 1500 $\mu$Hz & 2000  $\mu$Hz & 900  $\mu$Hz \\ 
 $A_{\rm max}$ & 3.26 $\pm$ 0.42 ppm& 4.02 $\pm$ 0.57 ppm &  3.82 $\pm$ 0.40 ppm & $\sim$1.7 ppm & $\sim$8.5 ppm  \\
 \hline
\end{tabular}
\end{table}