\begin{table}%t3
\par
\caption{\label{t3}Planetary parameters relevant to auroral studies.}             
%\centerline
 {\begin{tabular}{c c c c c c c c c c}   % 8 columns 
\hline\hline       
\noalign{\smallskip}
Planet & Average solar & Rotation & Equatorial & Surface & Magnetic & 
FUV aurora     & X-ray aurora & Disk X-ray & Magnetospheric \\ 
       & distance  & period & radius & magnetic field & moment & 
average input & total average & average & ions max. \\
& (AU)\tablefootmark{a} & (h)\tablefootmark{a} & (Earth = 1)\tablefootmark{a,b} & (G)\tablefootmark{a} &(Earth~= 1)\tablefootmark{a} &power 
(GW)\tablefootmark{c} & power (MW)\tablefootmark{d} & power (MW) & density (cm$^{\rm -3}$)\tablefootmark{a} \\
\hline\\[-3.2mm]
 Earth   & 1.0 & 23.9 & 1 & 0.31 & 1& 1--100 &10--30  & 40\tablefootmark{d} & 
1--4000  \\
 Jupiter & 5.2 & 9.9  & 11.2 & 4.28 & 20~000 & few $\times$ 10$^4$ & 400--1000  & 500--2000\tablefootmark{d}  & $>$3000   \\
 Saturn  & 9.6 & 10.7 & 9.4 & 0.22 & 600  & 10$^2$--10$^3$ & ? & $\leq$230\tablefootmark{e} & 100?   \\  
 Uranus  & 19.2 & 17.2 & 4.0 & 0.23 & 50 & $\la$40\tablefootmark{f} & ? & ? & 3 \\
 Neptune & 30.1 & 16.1 & 3.9 & 0.14 & 25 & $\la$0.1\tablefootmark{f} & ? & ? & 2 \\
\hline             
\end{tabular}}
\tablefoot{\tablefoottext{a}{From {\it The New Solar System}, ed. J. K. Beatty, C. Collins Petersen, \& A. Chaikin  1999 (Cambridge University Press).}
\tablefoottext{b}{For the outer planets, radius at 1 bar atmospheric pressure.}
\tablefoottext{c}{Clarke et~al. (\cite{Clarke_05}).}
\tablefoottext{d}{Bhardwaj et~al. (\cite{Bhardwaj_07}).}
\tablefoottext{e}{This paper.}
\tablefoottext{f}{Bhardwaj \& Gladstone (\cite{BG_00}).}}
\vspace*{2mm}
\end{table}