\begin{table}%t4
%\centering
\par
 \caption{\label{parameters}Resulting parameters for the model calculations. The isotope ratio 
is as follows: $^{12}$C$^{16}$O$_2$:$^{13}$C$^{16}$O$_2$:$^{16}$O$^{12}$C$^{18}$O.}
\small\begin{tabular}{lrrrl} 
\hline\hline
  & $T_{\rm ex}$ & $N$ & $r$ & isotope ratio \\
  &  (K)         & (cm$^{-2}$)    &  ($R_*$)   & \\ \hline
EP~Lyr        & 900 & $8\times10^{18}$ & 4.7 & 0.7 : 0.2 : 0.1 \\
HD~52961 & 800  & $5\times10^{18}$ & 4.7 & 0.93 : 0.05 : 0.02 \\
\hline
\end{tabular}
\end{table}