2011 XC2

' is a near-Earth asteroid roughly in diameter that passed less than 1 lunar distance from Earth on 3 December 2011.
From mid October 2011 until 3 December 2011 15:00 UT the small dim asteroid had an elongation less than 60 degrees from the Sun. On 3 December 2011 at 15:20 UT the asteroid passed from Earth and at 16:20 UT passed from the Moon. The asteroid was then discovered on 8 December 2011 by Lincoln Near-Earth Asteroid Research at an apparent magnitude of 19 using a reflecting telescope. At the time of discovery the asteroid was near opposition to the Sun.
It has an observation arc of 22 days with an uncertainty parameter of 7. Virtual clones of the asteroid that fit the uncertainty region in the known trajectory show a 1 in 455,000 chance that the asteroid will impact Earth on 2 December 2056. With a 2056 Palermo Technical Scale of −4.35, the odds of impact by in 2056 are about 22387 times less than the background hazard level of Earth impacts which is defined as the average risk posed by objects of the same size or larger over the years until the date of the potential impact. Using the nominal orbit, JPL Horizons shows that the asteroid will be from Earth on 2 December 2056.
Asteroid Date Nominal approach distance Min. distance Max. distance Absolute magnitude Size
1914-12-31 0.606 0.604 0.608 19.4 279–900
1918-09-17 0.911 0.909 0.913 17.9 556–1795
1925-08-30 0.903 0.901 0.905 18.5 443–477
1936-01-06 0.553 0.553 0.553 23.2 48–156
1971-04-11 0.616 0.587 0.651 21.2 122–393
1976-10-17 0.854 0.853 0.855 22.3 73–237
1981-11-04 0.818 0.813 0.823 21.4 111–358
1991-04-08 0.847 0.676 1.027 23.3 46–149
2001-11-08 0.454 0.318 3.436 20.7 153–494
2002 MN 2002-06-14 0.312 0.312 0.312 23.6 40–130
2011-11-08 0.845 0.845 0.845 21.9 320–400
' 2011-12-03 0.904 0.901 0.907 23.2 48–156
2018 AH 2018-01-02 0.773 0.772 0.773 22.5 67–216
2018-04-15 0.502 0.501 0.503 23.7 35–135
2028-06-26 0.647 0.647 0.647 18.2 921–943
99942 Apophis 2029-04-13 0.0981 0.0963 0.1000 19.7 310–340
2041-04-08 0.283 0.274 0.354 23.3 46–149
2047-06-06 0.789 0.251 38.135 22.4 70–226
2058-09-22 0.918 0.917 0.919 23.8 37–119
2065-05-28 0.865 0.856 0.874 20.7 153–494
2075-11-08 0.592 0.499 0.752 21.9 320–400
2101-01-02 0.621 0.615 0.628 21.0 133–431
2129-10-19 0.239 0.155 0.381 22.7 61–197
101955 Bennu 2135-09-25 0.780 0.308 1.406 20.19 472–512
2140-12-01 0.634 0.631 0.637 19.3 427–593
2146-03-23 0.896 0.744 1.288 22.8 58–188
2148-01-22 0.771 0.770 0.771 21.1 127–411
2156-02-13 0.685 0.652 6.856 22.9 56–179
2156-12-16 0.998 0.955 1.215 21.6 101–327

Asteroid	Date	Nominal approach distance	Min. distance	Max. distance	Absolute magnitude	Size
	1914-12-31	0.606	0.604	0.608	19.4	279–900
	1918-09-17	0.911	0.909	0.913	17.9	556–1795
	1925-08-30	0.903	0.901	0.905	18.5	443–477
	1936-01-06	0.553	0.553	0.553	23.2	48–156
	1971-04-11	0.616	0.587	0.651	21.2	122–393
	1976-10-17	0.854	0.853	0.855	22.3	73–237
	1981-11-04	0.818	0.813	0.823	21.4	111–358
	1991-04-08	0.847	0.676	1.027	23.3	46–149
	2001-11-08	0.454	0.318	3.436	20.7	153–494
2002 MN	2002-06-14	0.312	0.312	0.312	23.6	40–130
	2011-11-08	0.845	0.845	0.845	21.9	320–400
'	2011-12-03	0.904	0.901	0.907	23.2	48–156
2018 AH	2018-01-02	0.773	0.772	0.773	22.5	67–216
	2018-04-15	0.502	0.501	0.503	23.7	35–135
	2028-06-26	0.647	0.647	0.647	18.2	921–943
99942 Apophis	2029-04-13	0.0981	0.0963	0.1000	19.7	310–340
	2041-04-08	0.283	0.274	0.354	23.3	46–149
	2047-06-06	0.789	0.251	38.135	22.4	70–226
	2058-09-22	0.918	0.917	0.919	23.8	37–119
	2065-05-28	0.865	0.856	0.874	20.7	153–494
	2075-11-08	0.592	0.499	0.752	21.9	320–400
	2101-01-02	0.621	0.615	0.628	21.0	133–431
	2129-10-19	0.239	0.155	0.381	22.7	61–197
101955 Bennu	2135-09-25	0.780	0.308	1.406	20.19	472–512
	2140-12-01	0.634	0.631	0.637	19.3	427–593
	2146-03-23	0.896	0.744	1.288	22.8	58–188
	2148-01-22	0.771	0.770	0.771	21.1	127–411
	2156-02-13	0.685	0.652	6.856	22.9	56–179
	2156-12-16	0.998	0.955	1.215	21.6	101–327