The 49 - 110 metre wide asteroid 2014 RF11 will make a close pass (38.4 lunar distances, 0.0986 AU), travelling at 3.84 km/second, to the Earth-Moon system on the 15th September 2014 @ 19:40 UT ±00:14.
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The Lunar Distance (LD), the distance between Earth and the Moon, equals 384,401 km, (or 0.00256 AU).