The 9 - 20 metre wide asteroid 2011 UX255 made a close pass (0.4 lunar distances, 0.0009 AU), travelling at 19.19 km/second, to the Earth-Moon system on the 28th October, 2011 @ 17:46 UT ±00:04.
Orbital elements:
2011 UX255 Earth MOID = 0.0007 AU
Epoch 2011 Aug. 27.0 TT = JDT 2455800.5 MPC
M 353.60593 (2000.0) P Q
n 0.35014751 Peri. 70.83983 +0.27238990 +0.95969498
a 1.9935877 Node 215.20135 -0.92174542 +0.23963231
e 0.7929289 Incl. 6.89515 -0.27602377 +0.14683969
P 2.81 H 27.4 G 0.15 U 7