L=mv0R=mRGMR=mGMR here M is mass of star $\begin{aligned}
& \frac{\mathrm{L}{\mathrm{B}}}{\mathrm{~L}{\mathrm{A}}}=\frac{\mathrm{m}{\mathrm{B}}}{\mathrm{~m}{\mathrm{A}}} \sqrt{\frac{\mathrm{R}{\mathrm{B}}}{\mathrm{R}{\mathrm{A}}}} \
& =4 \sqrt{2} \sqrt{\frac{2}{1}} \
& \frac{\mathrm{L}_{\mathrm{B}}}{\mathrm{L}_{\mathrm{A}}}=8
\end{aligned}$