List of asteroid close approaches to Earth in 2011

Asteroids which came closer to Earth than the Moon in 2011 by time of discovery

After closest approach: 19 (59.4%)
< 24 hours before: 1 (3.1%)
up to 7 days before: 10 (31.2%)
> one week before: 0 (0.0%)
> 7 weeks before: 0 (0.0%)
> one year before: 2 (6.2%)

Other years
2009, 2010, 2011, 2012, 2013

Below is the list of asteroid close approaches to Earth in 2011.

Warning times by size

A list of known near-Earth asteroid close approaches less than 1 lunar distance (384,400 km or 0.00257 AU) from Earth in 2011, based on the close approach database of the Center for Near-Earth Object Studies (CNEOS).^[1]

The CNEOS database of close approaches lists some close approaches a full orbit or more before the discovery of the object, derived by orbit calculation. The list below only includes close approaches that are evidenced by observations, thus the pre-discovery close approaches would only be included if the object was found by precovery, but there was no such close approach in 2011.

This list and the relevant databases do not consider impacts as close approaches, thus this list does not include any of the objects that collided with Earth's atmosphere in 2011, none of which were discovered in advance, but were observed visually or recorded by sensors designed to detect detonation of nuclear devices.

Rows highlighted red indicate objects which were not discovered until after closest approach

Rows highlighted yellow indicate objects discovered less than 24 hours before closest approach

Rows highlighted green indicate objects discovered more than one week before closest approach

Rows highlighted turquoise indicate objects discovered more than 7 weeks before closest approach

Rows highlighted blue indicate objects discovered more than one year before closest approach
(i.e. objects successfully cataloged on a previous orbit, rather than being detected during final approach)

Date of closest approach	Date discovered	Object	Nominal geocentric distance (AU)^{[note 1]}	Size (m) (approximate) ^{[note 2]}	(H)	Closer approach to Moon	Refs^[2]^[3]
2011-01-11	2011-01-13	2011 AM₃₇	0.00086 AU (129,000 km; 80,000 mi)	2.8–6.2	29.9^[4]		data · 2011 AM₃₇
2011-01-17	2011-01-14	2011 AN₅₂	0.00213 AU (319,000 km; 198,000 mi)	5.1–11	28.6^[5]	Yes	data · 2011 AN₅₂
2011-01-20	2011-01-24	2011 BY₁₀	0.00238 AU (356,000 km; 221,000 mi)	10–23	27.1^[6]	Yes	data · 2011 BY₁₀
2011-01-25	2011-01-26	2011 BW₁₁	0.00086 AU (129,000 km; 80,000 mi)	5.8–13	28.3^[7]		data · 2011 BW₁₁
2011-01-31	2011-02-05	2011 CA₄	0.00165 AU (247,000 km; 153,000 mi)	10–23	27.1^[8]		data · 2011 CA₄
2011-02-04	2011-02-04	2011 CQ1	0.000079 AU (11,800 km; 7,300 mi)	1–2.3	32.1^[9]		data · 2011 CQ₁
2011-02-06	2011-02-07	2011 CF₂₂	0.00027 AU (40,000 km; 25,000 mi)	1.8–4	30.9^[10]		data · 2011 CF₂₂
2011-02-09	2011-02-07	2011 CA₇	0.00069 AU (103,000 km; 64,000 mi)	2.3–5.2	30.3^[11]		data · 2011 CA₇
2011-02-23	2011-02-27	2011 DU₉	0.00192 AU (287,000 km; 178,000 mi)	12–27	26.7^[12]		data · 2011 DU₉
2011-03-03	2011-03-04	2011 EN₁₁	0.00166 AU (248,000 km; 154,000 mi)	7–16	27.9^[13]		data · 2011 EN₁₁
2011-03-07	2011-03-05	2011 EY₁₁	0.000876 AU (131,000 km; 81,400 mi)	5.3–12	28.5^[14]		data · 2011 EY₁₁
2011-03-08	2011-03-10	2011 EM₄₀	0.00162 AU (242,000 km; 151,000 mi)	6.7–15	28.0^[15]		data · 2011 EM₄₀
2011-03-16	2011-03-15	2011 EB₇₄	0.00219 AU (328,000 km; 204,000 mi)	11–25	26.9^[16]		data · 2011 EB₇₄
2011-04-06	2011-04-04	2011 GW₉	0.00133 AU (199,000 km; 124,000 mi)	6.4–14	28.1^[17]		data · 2011 GW₉
2011-04-06	2011-04-04	2011 GP₂₈	0.00064 AU (96,000 km; 59,000 mi)	3.5–7.8	29.4^[18]		data · 2011 GP₂₈
2011-05-05	2011-05-08	2011 JV₁₀	0.00232 AU (347,000 km; 216,000 mi)	3.1–6.8	29.7^[19]	Yes	data · 2011 JV₁₀
2011-06-02	2009-01-16	2009 BD	0.00232 AU (347,000 km; 216,000 mi)	6.4–14	28.1^[20]		data · 2009 BD
2011-06-27	2011-06-22	2011 MD	0.000125 AU (18,700 km; 11,600 mi)	6.7–15	28.0^[21]		data · 2011 MD
2011-07-24	2011-08-06	2011 PU₁	0.00224 AU (335,000 km; 208,000 mi)	20–45	25.6^[22]	Yes	data · 2011 PU₁
2011-07-28	2011-07-31	2011 OD₁₈	0.00115 AU (172,000 km; 107,000 mi)	13–30	26.5^[23]		data · 2011 OD₁₈
2011-09-27	2011-09-23	2011 SE₅₈	0.00159 AU (238,000 km; 148,000 mi)	7.3–16	27.8^[24]		data · 2011 SE₅₈
2011-09-28	2011-10-01	2011 TO	0.00086 AU (129,000 km; 80,000 mi)	13–29	26.6^[25]		data · 2011 TO
2011-09-30	2011-09-29	2011 SM₁₇₃	0.00194 AU (290,000 km; 180,000 mi)	7.3–16	27.8^[26]		data · 2011 SM₁₇₃
2011-10-12	2011-10-17	2011 UT	0.00152 AU (227,000 km; 141,000 mi)	18–41	25.8^[27]	Yes	data · 2011 UT
2011-10-17	2009-10-15	2009 TM₈	0.00226 AU (338,000 km; 210,000 mi)	5.6–12	28.4	Yes	data · 2009 TM₈
2011-10-26	2011-10-27	2011 UL₁₆₉	0.00177 AU (265,000 km; 165,000 mi)	5.9–13	28.3^[28]		data · 2011 UL₁₆₉
2011-10-28	2011-10-30	2011 UX₂₅₅	0.00093 AU (139,000 km; 86,000 mi)	8.8–20	27.4^[29]		data · 2011 UX₂₅₅
2011-11-08	2005-12-28	(308635) 2005 YU55	0.00217 AU (325,000 km; 202,000 mi)	360	21.9^[30]	Yes	data · 2005 YU₅₅
2011-12-03	2011-12-08	2011 XC2	0.00232 AU (347,000 km; 216,000 mi)	61–140	23.2^[31]	Yes	data · 2011 XC₂
2011-12-28	2011-12-29	2011 YC₄₀	0.00071 AU (106,000 km; 66,000 mi)	3.1–7	29.6^[32]		data · 2011 YC₄₀
2011-12-29	2012-01-01	2012 AQ	0.00180 AU (269,000 km; 167,000 mi)	1.9–4.3	30.7^[33]		data · 2012 AQ
2011-12-30	2011-12-31	2011 YC₆₃	0.00161 AU (241,000 km; 150,000 mi)	4.2–9.4	29.0^[34]		data · 2011 YC₆₃

This sub-section visualises the warning times of the close approaches listed in the above table, depending on the size of the asteroid. The sizes of the charts show the relative sizes of the asteroids to scale. For comparison, the approximate size of a person is also shown. This is based the absolute magnitude of each asteroid, an approximate measure of size based on brightness.

Absolute magnitude H ≥ 30 (smallest)