* Astronomy

Orbital elements:
2012 XN55                                                Earth MOID = 0.0660 AU
Epoch 2012 Sept. 30.0 TT = JDT 2456200.5                MPC
M  40.29874              (2000.0)            P               Q
n   1.52155164     Peri.   14.96065     -0.00914182     +0.88200597
a   0.7486490      Node   256.31836     -0.96002084     -0.13957030
e   0.4535948      Incl.   29.00650     -0.27977922     +0.45009510
P   0.65           H   24.0           G   0.15           U   8

MPEC 2012 - X48

The 41 - 92 metre wide asteroid 2012 XN55 made a close pass (27.8 lunar distances, 0.0715 AU), travelling at 16.05 km/second, to the Earth-Moon system on the 6th December, 2012 @ 22:06 UT ±00:24. 

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The Lunar Distance (LD), the distance between Earth and the Moon, equals 384,401 km, (or 0.00256 AU).