List of asteroid close approaches to Earth in 2021

Below is the list of asteroid close approaches to Earth in 2021.

Time of discovery of asteroids which came closer to Earth than the Moon in 2021

After closest approach: 2 (20.0%)< 24 hours before: 4 (40.0%)up to 7 days before: 4 (40.0%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

  •   After closest approach: 2 (20.0%)
  •   < 24 hours before: 4 (40.0%)
  •   up to 7 days before: 4 (40.0%)
  •   > one week before: 0 (0.0%)
  •   > 7 weeks before: 0 (0.0%)
  •   > one year before: 0 (0.0%)

Timeline of known close approaches less than one lunar distance from Earth

A list of known near-Earth asteroid close approaches less than 1 lunar distance (0.0025696 AU (384,410 km; 238,860 mi)) from Earth in 2021.[note 1]

For reference, the radius of Earth is about 0.0000426 AU (6,370 km; 3,960 mi) or 0.0166 lunar distances. Geosynchronous satellites have an orbit with semi-major axis length of 0.000282 AU (42,200 km; 26,200 mi) or 0.110 lunar distances.

  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[note 2] Approx.
size (m)		 (H)
(abs. mag)		 Closer
approach
to Moon[note 3]		 References[1][2]
(AU) (Lunar
distance)
2021-01-012021-01-012021 AA0.001586 AU (237,300 km; 147,400 mi)0.6211–2426.9—data · 2021 AA
2021-01-032021-01-032021 AH0.000333 AU (49,800 km; 31,000 mi)0.135.4–1228.5—data · 2021 AH
2021-01-042021-01-052021 AH80.000354 AU (53,000 km; 32,900 mi)0.143.2–7.329.6—data · 2021 AH8
2021-01-092021-01-082021 AS20.000717 AU (107,300 km; 66,600 mi)0.283.3–7.529.5—data · 2021 AS2
2021-01-162021-01-182021 BR20.000492 AU (73,600 km; 45,700 mi)0.161.8–4.130.8—data · 2021 BR2
2021-01-182021-01-172021 BK0.000751 AU (112,300 km; 69,800 mi)0.292.3–5.230.3—data · 2021 BK
2021-01-182021-01-172021 BV10.001606 AU (240,300 km; 149,300 mi)0.626.6–1528.0—data · 2021 BV1
2021-01-182021-01-172021 BO0.000160 AU (23,900 km; 14,900 mi)0.060.69–1.632.9—data · 2021 BO
2021-01-202021-01-182021 BO10.001678 AU (251,000 km; 156,000 mi)0.654.0–9.029.1—data · 2021 BO1
2021-02-112021-02-052021 CO0.002419 AU (361,900 km; 224,900 mi)0.9424–5325.3—data · 2021 CO

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.

Abs Magnitude 30 and greater

Silhouette of man standing and facing forward

(size of a person for comparison)

After closest approach: 1 (33.3%)< 24 hours before: 1 (33.3%)up to 7 days before: 1 (33.3%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Abs Magnitude 29-30

After closest approach: 1 (33.3%)< 24 hours before: 0 (0.0%)up to 7 days before: 2 (66.7%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Absolute Magnitude 28-29

After closest approach: 0 (0.0%)< 24 hours before: 2 (100.0%)up to 7 days before: 0 (0.0%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)


Absolute Magnitude 26-27

After closest approach: 0 (0.0%)< 24 hours before: 1 (100.0%)up to 7 days before: 0 (0.0%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Absolute Magnitude 25-26

After closest approach: 0 (0.0%)< 24 hours before: 0 (0.0%)up to 7 days before: 1 (100.0%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)


Notes
  1. For a list of current Earth close approaches see Close Approaches and NEO Earth Close Approaches
  2. Distance from the center of Earth to the center of the object. See the NASA/JPL Solar System Dynamics Glossary: Geocentric. Earth has a radius of approximately 6,400 km (0.166 LD).
  3. Objects that approached closer to the Moon than Earth are marked with a check.

Additional examples

An example list of near-Earth asteroids that passed or will pass more than 1 lunar distance (384,400 km or 0.00256 AU) from Earth in 2021.

Object Size
(meters)		 Nearest approach
(lunar
distances)		 Date Ref
2018 RB120-26018.272021-02-07JPL · CAD
(456537) 2007 BG330-75022.352021-02-26JPL · CAD
2016 DV129-654+3.6
−4		2021-03-02JPL · CAD
(231937) 2001 FO32770-1,7005.252021-03-21JPL · CAD
(441987) 2010 NY65140-31015.542021-06-25JPL · CAD
2016 AJ193480-1,1008.922021-08-21JPL · CAD
3361 Orpheus 420-93015.012021-11-21JPL · CAD
Planet Venus[note2 1]—107.42021-12-31JPL

Notes
  1. For comparison as closest Venus approach is 2022-Jan-08 at 103 LD.

Potentially hazardous asteroid discoveries

A list of near-Earth asteroids classified as potentially hazardous objects discovered in 2021. As of January 2021, 2021 AV7 is the largest potentially hazardous object discovered so far in 2021.[3]

Object Discovery date Size
(meters)
[note3 1]		 (H)
(abs. mag)		 Earth MOID
(AU/LD)		 Ref
2021 AE42021-01-06120-26021.80.0374 AU (14.6 LD)data · 2021 AE4
2021 AL62021-01-13210-47020.50.0091 AU (3.5 LD)data · 2021 AL6
2021 AV72021-01-15460-1,00018.80.0005 AU (0.19 LD)data · 2021 AV7
2021 AF82021-01-14270-59020.00.0225 AU (8.8 LD)data · 2021 AF8
2021 BW2021-01-17210-47020.50.0263 AU (10.2 LD)data · 2021 BW
2021 BF32021-01-16130-28021.60.0286 AU (11.1 LD)data · 2021 BF3
2021 BM32021-01-31130-30021.50.0428 AU (16.7 LD)data · 2021 BM3

Notes
  1. Assuming albedo range of 0.05–0.25

See also

References
  1. "JPL Small-Body Database Browser". JPL Solar System Dynamics. NASA Jet Propulsion Laboratory.
  2. "MPC Database". IAU Minor Planet Center. International Astronomical Union. Retrieved 1 January 2021.
  3. "JPL Small-Body Database Search Engine: unnumbered objects and PHAs". JPL Solar System Dynamics. Jet Propulsion Laboratory. Retrieved 23 January 2021.
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