[填空题]
Two stars 15 light-years away are bah vyf:g6j kz4(8 qpv/l6o3 vkjrely resolved by a 55-xhz*fl 4t h4 0w hsk))l,hc(bb u9+hdq$cm$ (mirror diameter) telescope. How far apart are the stars? Assume $\lambda=550\mathrm{~nm.}$ and that the resolution is limited by diffraction. $ \times10^{11 }\;m$
