\begin{table}%t4
  \caption{\label{tab_abund_models}Variation in the abundances for the included elements with [$x$]~=~log(mass
    fraction/solar mass fraction) of species $x$, following
    \citet{grevesse2000} for the solar abundances.} 
%\centering
\par
    \small\begin{tabular}{rccccc}
      \hline\hline
                                %
      \# & [C] & [N] & [O] & [Si] & [H]\\
                                %
\hline
      1 & 0  & 0 & 0 & 0 & $-$10  \\
      2 & $-$3                  & 1 & $-$3                 & 0 & $-$10  \\
      3 & $-$3                  & 1 & $-$3                 & $-$3                 & $-$10  \\
      4 & 0  & 0 & 0 & 0 & $-$6, $-$5, $-$3, $-$2  \\
     \hline
    \end{tabular}
 \end{table}