List of asteroid close approaches to Earth in 2011


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


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

Timeline of close approaches less than one lunar distance from Earth in 2011

A list of known near-Earth asteroid close approaches less than 1 lunar distance from Earth in 2011, based on the close approach database of the Center for Near-Earth Object Studies.
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.
Date of
closest
approach		Date
discovered		ObjectNominal geocentric
distance 		Size
Closer
approach
to Moon		Refs
2011-01-112011-01-132.8–6.229.9
2011-01-172011-01-145.1–1128.6Yes
2011-01-202011-01-2410–2327.1Yes
2011-01-252011-01-265.8–1328.3
2011-01-312011-02-0510–2327.1
2011-02-042011-02-041–2.332.1
2011-02-062011-02-071.8–430.9
2011-02-092011-02-072.3–5.230.3
2011-02-232011-02-2712–2726.7
2011-03-032011-03-047–1627.9
2011-03-072011-03-055.3–1228.5
2011-03-082011-03-106.7–1528.0
2011-03-162011-03-1511–2526.9
2011-04-062011-04-046.4–1428.1
2011-04-062011-04-043.5–7.829.4
2011-05-052011-05-083.1–6.829.7Yes
2011-06-022009-01-166.4–1428.1
2011-06-272011-06-226.7–1528.0
2011-07-242011-08-0620–4525.6Yes
2011-07-282011-07-3113–3026.5
2011-09-272011-09-237.3–1627.8
2011-09-282011-10-0113–2926.6
2011-09-302011-09-297.3–1627.8
2011-10-122011-10-1718–4125.8Yes
2011-10-172009-10-155.6–1228.4Yes
2011-10-262011-10-275.9–1328.3
2011-10-282011-10-308.8–2027.4
2011-11-082005-12-2836021.9Yes
2011-12-032011-12-0861–14023.2Yes
2011-12-282011-12-293.1–729.6
2011-12-292012-01-011.9–4.330.7
2011-12-302011-12-314.2–9.429.0

Warning times by size

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

Absolute magnitude 30 > H ≥ 29
Absolute magnitude 29 > H ≥ 28
Absolute magnitude 27-28
Absolute magnitude 27 > H ≥ 26
Absolute magnitude 26 > H ≥ 25
'''Absolute magnitude 25 > H '''