* Astronomy

Orbital elements:
2009 YS                                                  Earth MOID = 0.0040 AU
Epoch 2010 Jan. 4.0 TT = JDT 2455200.5                  MPC
M  31.00083              (2000.0)            P               Q
n   0.75668810     Peri.  338.64016     +0.49466307     -0.86124185
a   1.1926823      Node    81.54687     +0.81346095     +0.41164093
e   0.1796653      Incl.    6.76364     +0.30592440     +0.29801714
P   1.30           H   25.3           G   0.15           U   8

MPEC 2009 - Y31

The 23 - 52 metre wide asteroid 2009 YS made a close pass (1.5 lunar distances, 0.0038 AU), travelling at 4.81 km/second, to the Earth-Moon system on the 12th December, 2009.

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