\begin{table}%t4
\caption{\label{let_ac}Solar abundance of C in the literature.}
\small%\centering
\par
\begin{tabular}{ll}
 \hline\hline\noalign{\smallskip}
$A$(C)      & Ref.   \\ 
 \hline 
8.67  $\pm$ 0.10  & \citet{lambert78}  \\ 
8.56  $\pm$ 0.04  & \citet{ag89}       \\ 
8.58  $\pm$ 0.13  & \citet{stuerenburg}\\ 
8.60  $\pm$ 0.05  & \citet{grevesse91} \\ 
8.60  $\pm$ 0.10  & \citet{biemont93}  \\ 
8.55             & \citet{grevesse94} \\ 
8.54             & \citet{takeda94}   \\ 
8.52  $\pm$ 0.06  & \citet{grevesse98} \\ 
8.52  $\pm$ 0.06  & \citet{grevesse00} \\ 
8.57  $\pm$ 0.03  & \citet{hhoxy}      \\ 
8.592 $\pm$ 0108   & \citet{hhoxy}      \\ 
8.39  $\pm$ 0.04  & \citet{allende02}  \\ 
8.39  $\pm$ 0.05  & \citet{asplund05}  \\ 
8.39  $\pm$ 0.05  & \citet{scott06}    \\ 
8.44  $\pm$ 0.06  & \citet{pin06}      \\ 
8.39  $\pm$ 0.05  & \citet{grevesse07} \\ 
8.43  $\pm$ 0.05  & \citet{asplund09}  \\ 
8.50  $\pm$ 0.06  & present work       \\
 \hline
\end{tabular} 
\end{table}