\begin{table}%t1
\caption{Main model parameters for the nominal case.} \label{tab:nom}
%\centering
\small
\begin{tabular}{ll}     
\hline\hline
\multicolumn{1}{c}{{Grains}}\\
material & \m \\ 
porosity  & compact grains ($P=0$)   \\ 
grain density & 3.5~g~cm$^{-3}$ \\
\cline{1-1}
\multicolumn{1}{c}{{Disc ("field'' population)}}\\ 
minimum size  & $s_{\rm min}=2~\mu$m\\  
maximum size &$s_{\rm max}=1$~cm\\
radial distribution & \citet{Au01} \\
optical thickness along radius \\
in the midplane &	$\tau_{\rm \|}=0.022$ \\
disc extension & $[20, 500]$~AU \\
\cline{1-1}
\multicolumn{1}{c}{{Initial planetesimal debris}}\\ 
minimum size & $s_{\rm min,pl}=0.1~\mu$m\\ 
maximum size &$s_{\rm max,pl}=1$~cm\\
size distribution (see  Eq.~(\ref{eq:dn}))  & $p_{\rm 0,pl}=-3.5 $ \\
initial mass of dust released  & $M_0=10^{20}$~g \\
distance from the star for \\
the planetesimal breakup &  $R_0=20$~AU \\
initial velocity of \\
the center of the mass &  $v_0=1.1v_{\rm kep} $ \\
\cline{1-1}
\multicolumn{1}{c}{{Collisional prescription}}\\ 
threshold energy, $s_0=1$~cm & $Q^*_0=10^7$~erg~g$^{-1}$ \\ 
power-law index (Eq.~(\ref{eq:Qth1})) & $p_Q=-0.2 $   \\ 
\multicolumn{2}{l}{{size distribution of debris (see  Eq.~(\ref{eq:dn_qi}))} }\\
{~~~~}minimum size & $s_{\rm min,col}=0.1~\mu$m\\ 
{~~~~}power-law indexes for $m<m_s$ & $q_1=1.5$ \\
{~~~~}power-law indexes for $m \geq m_s$ &$q_2=1.83$ \\      
{~~~~}position of the slope change  &  $m_s=M_{\rm lf}/3$ \\
\hline
\end{tabular}
\end{table}