Answer
195 m.
Work Step by Step
The angular size of the object is $ \theta=\frac{1.40\times10^8m}{4.3(9.461\times10^{15}m)}=3.44\times10^{-9}rad$.
Use Rayleigh’s criterion to find the resolution.
The resolving power is $ \theta_{r}=1.22\frac{\lambda}{D}$.
$$3.44\times10^{-9}rad =1.22\frac{\lambda}{ D}$$
$$D =1.22\frac{550\times10^{-9}m }{3.44\times10^{-9}rad }=195m$$
