The 36 - 80 metre wide asteroid 2011 YC made a close pass (30.8 lunar distances, 0.0792 AU), travelling at 8.62 km/second, to the Earth-Moon system on the 14th December, 2011 @ 20:24 UT ±00:24.
Orbital elements:
2011 YC Earth MOID = 0.0733 AU
Epoch 2012 Mar. 14.0 TT = JDT 2456000.5 MPC
M 41.11950 (2000.0) P Q
n 0.45096441 Peri. 357.81412 +0.12019321 -0.96308798
a 1.6841258 Node 85.21758 +0.91445863 +0.01296804
e 0.3725690 Incl. 13.98718 +0.38641818 +0.26887426
P 2.19 H 24.4 G 0.15 U 8