\begin{table}%T2
\caption{\label{tab-orbit}Orbital solution for WR~20a assuming a circular orbit and an orbital period of $3.675$~days. $T_0$~refers to the time of conjunction with the primary being behind. $\gamma$, $K$ and~$a~\sin{i}$ denote respectively the systemic velocity, the amplitude of the radial velocity curve and the projected separation between the centre of the star and the centre of mass of the binary system. $R_{\rm RL}$ stands for the radius of a sphere with a volume equal to that of the Roche lobe computed according to the formula of Eggleton (\cite{Egg}). All error bars indicate 1-$\sigma$~uncertainties.}
%\centering
\par
\begin{tabular}{l r r}
\hline\hline
 & Primary & Secondary\\
\hline
$T_0$(HJD$-2~450~000$) & \multicolumn{2}{c}{$3043.480 \pm 0.014$} \\
$\gamma$ (km~s$^{-1}$) & $18.8 \pm 5.6$ & $-3.5 \pm 5.7$ \\
$K$ (km~s$^{-1}$) & $353.1 \pm 8.6$ & $362.6 \pm 8.8$ \\
$a\sin i$ ($R_{\odot}$) & $25.6 \pm 0.2$ & $26.3 \pm 0.6$ \\ 
$q = m_1/m_2$ & \multicolumn{2}{c}{$1.03 \pm 0.03$} \\
$m\sin^3 i$ ($M_{\odot}$) & $70.7 \pm 4.0$ & $68.8 \pm 3.8$ \\
R$_{\rm RL}~\sin{i}$ ($R_{\odot}$) & $19.8 \pm 0.2$ & $19.5 \pm 0.2$ \\ 
\hline
\end{tabular}
\end{table}