\begin{table}%T5
%\centering
\small
\caption{Polarization at quadrature 
  $\langle Q/I \rangle_{90^\circ}$ (phase angle
  $\alpha=90^\circ$) for model planets with semi-infinite 
  Rayleigh scattering
  atmosperes (single scattering albedo $\omega$) and with finite 
  Rayleigh scattering layer (optical
  thickness $b_\tau$) and ground albedo $A_{\rm ground}$. Results
  are based on Monte Carlo simulations.}
\label{exoplanetpol}
\begin{tabular}{ccccc}
\hline\hline
\multicolumn{4}{l}{Semi-infinite Rayleigh scattering atmospheres}\\
\hline         
$\omega$ & $\langle Q/I \rangle_{90^\circ}$  & 
            & $\omega$ & $\langle Q/I \rangle_{90^\circ}$ \\
\hline
1.0      & 32\%    &        & 0.80     & 67\% \\
0.99     & 40\%    &        & 0.60     & 80\% \\
0.95     & 50\%    &        & 0.40     & 89\% \\
0.90     & 57\%    &        & 0.20     & 95\% \\
\hline
\multicolumn{4}{l}{Finite Rayleigh scattering atmospheres}\\
\hline       
$b_\tau$   &        &    & $\langle Q/I \rangle_{90^\circ}$ \\
\par
           & $A_{\rm ground}=$ & 0.80 & 0.25 & 0.0  \\ 
\hline 
1.0     & & ~~~35\%~~~   & 53\%   & 64\% \\
0.5     & &  27\%   & 52\%   & 76\% \\
0.25    & &  18\%   & 42\%   & 85\% \\
0.15    & &  12\%   & 32\%   & 90\% \\
0.10    & &  9\%    & 25\%   & 92\% \\
0.05    & &  5\%    & 14\%   & 95\% \\
0.02    & &  2\%    & 7\%    & 97\% \\
\hline 
\end{tabular}
\end{table}