Orbital elements:
2011 UK21 Earth MOID = 0.0078 AU
Epoch 2011 Aug. 27.0 TT = JDT 2455800.5 MPC
M 325.49402 (2000.0) P Q
n 0.43773761 Peri. 23.22168 +0.55633286 -0.82775627
a 1.7178826 Node 33.10847 +0.73993071 +0.45355928
e 0.4295811 Incl. 7.66885 +0.37814852 +0.33030824
P 2.25 H 25.1 G 0.15 U 6
The 25 - 56 metre wide asteroid 2011 UK21 will make a close pass (11.1 lunar distances, 0.0285 AU), travelling at 8.26 km/second, to the Earth-Moon system on the 23rd October, 2011 @ 00:54 UT ±00:06.