\begin{table}%t2
\caption{\label{tab2}Descriptions of the chemistry  of the models calculated for this work.}
%\centering
\par
\begin{tabular}{ccccccc}
\hline\hline\noalign{\smallskip}
Name & Description & $Z$ & [C/Fe] & [N/Fe] & [O/Fe] & Reference\\
\hline
\multicolumn{7}{c}{$Z=0.0006$} \\
CNOx1s & Solar-scaled      &0.0006&0.00 &0.00 &0.00   &GS1999\\
CNOx1a &[$\alpha$/Fe] = 0.40  &0.0006&0.00 &0.00 &0.40 &GS1999\\
\hline
\multicolumn{7}{c}{$Z=0.0002$} \\
CNOx1s                   &Solar-scaled&0.0002&0.00 &0.00 &0.00   &GS1999\\
CNOx1a                   &[$\alpha$/Fe] = 0.40 &0.0002&0.00 &0.00 &0.40 &GS1999\\
CNO$\uparrow$            & total(CNO) = 1.6      &0.0003&0.00&1.40&0.20&this work\\
\hline
\end{tabular}
\end{table}