\begin{table}%t2
%\centering
\par
\caption{\label{DUSTY_input}Range and step of the DUSTY input parameters. } 
\begin{tabular}{lll} \hline \hline 
Parameter   & Range   & Step \\ \hline
$\alpha$    & 0.2--2.5  &  0.1    \\ 
$Y$\tablefootmark{a}         & 50--2000   & 10  \\
$r_{\rm inf}$    &  5--200        & 2    \\ 
$\tau_{100}$ & 0.1--10.  & 0.1 \\
$T_{\rm in}$     & 300 K    & Fixed \\
$T_*$       & 5000 K    & Fixed \\ \hline 
\end{tabular}
\tablefoot{\tablefoottext{a}{$Y = r_{\rm out}/r_{\rm in}$.}}
\end{table}