\begin{table}%t1
\caption{\label{tab:summary_features}Summary of properties of the main types of emission profiles.}
%\centering
\par
\begin{tabular}{lcll}
\hline\hline\noalign{\medskip}
Feature &  Velocity (km~s$^{-1}$) &  Lines  &  Proposed origin \\
\hline
main peak & +23 & almost all & Western jet \\
high-velocity blue wing & up to 350 & almost all & stellar wind \\
high-velocity red wing & up to 450 & only permitted lines & accretion \\
plateau & ${\sim}0{-}5$ & [SII], [OI] 6300, [OI] 6364 & rotation? \\
\hline
\end{tabular}
\end{table}