* Astronomy

rbital elements:
2012 PX                                                  Earth MOID = 0.0017 AU
Epoch 2012 Sept. 30.0 TT = JDT 2456200.5                MPC
M   0.10118              (2000.0)            P               Q
n   0.29148008     Peri.  198.99714     +0.96624581     -0.25758770
a   2.2528388      Node   175.92288     +0.24334710     +0.90723887
e   0.5643850      Incl.    3.38337     +0.08456486     +0.33251499
P   3.38           H   23.2           G   0.15           U   8

MPEC 2012 - P20

The 61 - 140 metre wide asteroid 2012 PX will make a close pass (17.6 lunar distances, 0.0452 AU), travelling at 9.94 km/second, to the Earth-Moon system on the 4th September, 2012 @ 16:29 UT ±06:05. 

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