\begin{table}%t2
%\centering
\par
      \caption{Per volume abundances of He, O and C elements in the water-poor Uranian
      subnebula. He, CO, and H$_2$O are the dominant species with hydrogen gas in
      the water-poor subnebula.\label{tab2}}
         \begin{tabular}[]{ll}
            \hline
	    \hline
            \noalign{\smallskip}
             Species X$_i$  & X$_i$/H$_2$ \\
           \noalign{\smallskip}
            \hline
           \noalign{\smallskip}
            He & 0.18 \\
            O & 0.05  \\
            C & 0.023  \\
	    CO & 0.023 \\
	    H$_2$O & 0.027 \\
            \hline
         \end{tabular}
\end{table}