Orbital elements:
2013 OP3 Earth MOID = 0.1964 AU
Epoch 2013 July 7.0 TT = JDT 2456480.5 MPC
M 351.03391 (2000.0) P Q
n 0.13065340 Peri. 202.99242 +0.98872028 +0.10371477
a 3.8464100 Node 150.41927 -0.07881516 +0.97376251
e 0.6906284 Incl. 12.64361 -0.12735923 +0.20255818
P 7.54 H 21.7 G 0.15
From 6 observations 2013 July 16-17.