\begin{table}%t1
\caption{\label{tab_lines}Strongest lines in F-G dwarf stars.}
%\centering
\par
\begin{tabular}{c c}
\hline\hline\noalign{\smallskip}
 Line & $\lambda$ \AA  \\
\hline
%  Ca $II K$ & 3933 \\ 
Ca $II H$ & 3962 \\
H$\delta$ & 4101 \\
H$\gamma$ & 4340 \\
H$\beta$ & 4861\\
Mg b  triplet & 5183\\
\hline
\end{tabular}
\tablefoot{The first column indicates the name of the line and the second its wavelength position in \AA.}
\end{table}