\begin{table}%t2
%\centering
\par
\caption{Fundamental parameters of the WN6ha stars of WR~20a and of their stellar winds as determined from our spectral analysis. Note that the luminosity and mass-loss rate are given for a single component. The mass loss rate is based on a clumped wind model with a volume filling factor of $f = 0.1$.\label{param}}
\begin{tabular}{l c}
\hline\hline
\multicolumn{1}{c}{Parameter} & \multicolumn{1}{c}{Value} \\
\hline
Mass ($M_{\odot}$) & $82.7 \pm 5.5$ (primary) \\
Mass ($M_{\odot}$) & $81.9 \pm 5.5$ (secondary) \\
$L_{\rm bol}$ ($L_{\odot}$) & $(1.15 \pm 0.15) \times 10^{6}$  \\
$T_{\rm eff}$ (K) & $43~000 \pm 2000$\\
$\dot{M}$ ($M_{\odot}$~yr$^{-1}$) & $8.5 \times 10^{-6}$\\
$R_*$ ($R_{\odot}$) & $19.3 \pm 0.5$ \\
$v_{\infty}$ (km~s$^{-1}$) & 2800 (adopted)\\
$\log{g}$ & 3.8 \\
$(B - V)_0$ & $-0.33$ \\
$(V - I)_0$ & $-0.36$ \\
$E(B - V)$ & $1.94 \pm 0.05$ \\
$A_{\rm V}$ (mag) & $6.02 \pm 0.16$ \\
$d$ (kpc) & $7.9 \pm 0.6$ \\
\hline
\end{tabular}
\end{table}