\begin{table}%t6
%\centering
\par
\caption{Comet production model parameters.
\label{model_param}}
\begin{tabular}{lccccccl}
\hline\hline
Comet                   & mm yyyy    & $Q_o$ & $r_o$ & $\delta v_{\textrm{o}}$ & $\alpha$  & $\tau$ & Reference \\
          &   & [10$^{29}$~s$^{-1}$] & [AU]     & [km s$^{-1}$]   & [s]    & \\
\hline
%C/1983 H1 (IAA)$^{~ a}$& 05 1983 & 0.33  & 1.005 & 1.8 & 3.0  & 5700 & Feldman et~al.~(1983)\\
%1P/Halley              & 11 1985 & 6.9  & 0.903 & 1.8 & 3.0  & 5800 & Krankowsky et~al.~(1986)\\
%C/1996 B2 (Hyakutake)  & 03 1996 & 1.7  & 1.090 & 1.8 & 3.0  & 5800 & Mumma et~al.~(1996)\\
C/1995 O1 (Hale-Bopp)  & 04 1997 & 100  & 0.914 & 1.8 & 3.0  & 5600 & Colom et~al.~(1999)\\
C/2001 A2-B (LINEAR)   & 07 2001 & 0.28 & 1.130 & 1.49 & 3.0  & 5400 & F. Bensch (priv.~comm.)\\
153P/Ikeya-Zhang       & 04 2002 & 0.92 & 1.000 & 1.77 & 3.21 & 5600 & Dello Russo et~al.~(2004)\\
C/2001 Q4 (NEAT)       & 05 2004 & 1.8  & 1.017 & 1.67 & 3.0  & 5800 & N. Biver (priv.~comm.)\\
C/2002 T7 (LINEAR)     & 05 2004 & 4.5  & 0.645 & 1.59 & 3.0  & 5800 & N. Biver (priv.~comm.)\\
\hline
\end{tabular}
\end{table}