\begin{table}%t1
%\centering
\par
\caption{\label{prev_obs}Previous observations and nucleus size estimates for 103P.}
\begin{tabular}{ccccccl}
\hline \hline\noalign{\smallskip}
Date & $R_{\rm h}$\tablefootmark{a} & $\Delta$\tablefootmark{b} & $\alpha$\tablefootmark{c} &$m_R$\tablefootmark{d} & $r_{\rm N}$\tablefootmark{e} & Ref.\tablefootmark{f} \\
\hline
\multicolumn{6}{l}{Ground-based optical:}\\
28/03/93 & 4.7 & 3.8 & 3.3 & 20.1 & $\le$$ 5.3$ & L00 \\
10/12/98 & 3.6 & 3.9 & 14.3 & 19.0 & $\le$$ 6.4$ & LF01 \\
08/06/99 & 4.6 & 4.2 & 12.5 & 20.1 & $\le$$ 6.3$ & L03 \\
06/03/05 & 3.2 & 2.3 & 5.0 & 18.7 & $\le$$ 4.1$ & S06 \\
03/04/05 & 3.4 & 2.5 & 7.9 & 19.1 & $\le$$ 4.3$ & ME08 \\
01/03/06 & 5.0 & 4.3 & 8.3 & 21.0 & $\le$$ 4.5$ & S08 \\
\hline
\multicolumn{6}{l}{Space-based infrared:}\\
05/02/98 & 1.2 & 0.9 & 53.2 & -- & $0.71\pm0.13$ & G04\tablefootmark{g} \\
12/08/08 & 5.5 & 4.9 & 9.5 & -- & $0.57\pm0.08$ & L09\\
\hline
\end{tabular}
\tablefoot{\tablefoottext{a}{Heliocentric distance (AU): All post-perihelion except for L09;} \tablefoottext{b}{geocentric distance (AU);}
\tablefoottext{c}{solar phase angle (degrees);} 
\tablefoottext{d}{\mbox{$R$-band} magnitude.}
\tablefoottext{e}{nucleus radius (or upper limit) in~km assuming 4\% albedo and phase function of 0.035~mag~deg$^{-1}$;}
\tablefoottext{f}{L00: \citet{Licandro00b}; LF01: \citet{Lowry+Fitzsimmons01}; L03: \citet{Lowry03}; S06, S08: \citet{Snodgrass06,Snodgrass08}; ME08: \citet{Epifani08}; G04: \citet{Groussin04}; L09: \citet{Lisse09};}
\tablefoottext{g}{based on a coma subtraction technique.}}
\end{table}