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List of asteroid close approaches to Earth in 2019

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List of asteroid close approaches to Earth in 2019
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Below is the list of asteroid close approaches to Earth in 2019.

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Simulated animation of 66391 Moshup (previously KW4), a binary system asteroid, which came within 15 lunar distances in May 2019
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Timeline of known close approaches less than one lunar distance from Earth

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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 2019, based on the close approach database of the Center for Near-Earth Object Studies (CNEOS).[1] 2019 was the first year ever when four close approaches of previously undiscovered asteroids were successfully predicted over a week in advance.

For reference, the radius of Earth is approximately 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. A number of known asteroids came closer than this in 2019.

The largest asteroid to pass within 1 LD of Earth in 2019 was 2019 OK with an estimated diameter of around 95 meters and an absolute magnitude of 23.3. The fastest asteroid to pass within 1 LD of Earth in 2019 was 2019 FC1 that passed Earth with a velocity with respect to Earth of 25.9 km/s (58,000 mph).[2][note 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 are only included if the object was found by precovery.

This list and relevant databases do not consider impacts as close approaches, thus this list does not include 2019 MO, an asteroid which was predicted to impact on Earth and burned up in its atmosphere, as well as several more objects that collided with Earth's atmosphere in 2019 which weren't discovered in advance, but were observed visually or recorded by sensors designed to detect detonation of nuclear devices.[3]

     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)

More information Date ofclosest approach, Date discovered ...

In addition to the confirmed asteroids on the above list, which feature in the CNEOS close approach database, there have been well-observed unconfirmed or confirmed but poorly observed objects with a 50% or greater chance of passing within 1 LD of the Earth, which are listed separately below.

More information Date ofclosest approach, Date discovered ...

Warning times by size

This sub-section visualises the warning times of the close approaches listed in the table of confirmed close approaches, 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)

Silhouette of man standing and facing forward
Silhouette of man standing and facing forward

(size of a person for comparison)

After closest approach: 8 (72.7%)< 24 hours before: 2 (18.2%)up to 7 days before: 1 (9.1%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Absolute magnitude 30 > H ≥ 29

After closest approach: 8 (57.1%)< 24 hours before: 2 (14.3%)up to 7 days before: 4 (28.6%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Absolute magnitude 29 > H ≥ 28

After closest approach: 15 (65.2%)< 24 hours before: 3 (13.0%)up to 7 days before: 5 (21.7%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Absolute magnitude 28 > H ≥ 27

After closest approach: 12 (70.6%)< 24 hours before: 1 (5.9%)up to 7 days before: 4 (23.5%)> one week before: 0 (0.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Absolute magnitude 27 > H ≥ 26

After closest approach: 2 (20.0%)< 24 hours before: 2 (20.0%)up to 7 days before: 3 (30.0%)> one week before: 3 (30.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Absolute magnitude 26 > H ≥ 25

After closest approach: 1 (50.0%)< 24 hours before: 0 (0.0%)up to 7 days before: 0 (0.0%)> one week before: 1 (50.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)

Absolute magnitude 25 > H (largest)

After closest approach: 1 (20.0%)< 24 hours before: 0 (0.0%)up to 7 days before: 3 (60.0%)> one week before: 1 (20.0%)> 7 weeks before: 0 (0.0%)> one year before: 0 (0.0%)
  •   After closest approach: 1 (20.0%)
  •   < 24 hours before: 0 (0.0%)
  •   up to 7 days before: 3 (60.0%)
  •   > one week before: 1 (20.0%)
  •   > 7 weeks before: 0 (0.0%)
  •   > one year before: 0 (0.0%)

Notes

  1. [N 1]
    2019 FC1 passed Earth with a velocity with respect to Earth of 25.9 km/s and was moving away from the Sun at 37.1 km/s.
  2. [N 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.
  3. [N 3]
    A perigee during the asteroid's capture as temporary satellite by Earth
  4. [N 4]
    Precovery around this close approach: 2019-01-17 & 2019-01-24
  5. [N 5]
    2019-07-04 is the official first observation date for this asteroid, credited to the SONEAR Observatory, Oliveira by the Minor Planet Center. However the object had been observed several times by other telescopes in the run up, but had not been recognised as an asteroid by their automated systems. See 2019 OK for more details
  6. [N 6]
    Distance error: 0.0012 AU, approach range: 0.40 to 1.36 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
  7. [N 7]
    Distance error: 0.000420 AU, approach range: 0.016 to 0.25 LD. There was a roughly 2% chance of impact. The asteroid is most likely between 1 and 14 meters across, so would probably be detectable. The asteroid is unconfirmed and will likely never receive a provisional designation.
  8. [N 8]
    distance error: 0.0008 AU, approach range: 0.27 to 0.90 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
  9. [N 9]
    distance error: 0.0010 AU, approach range: 0.30 to 1.07 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
  10. [N 10]
    the asteroid is unconfirmed and will likely never receive a provisional designation.
  11. [N 11]
    distance error: 0.0004 AU, approach range: 0.39 to 0.70 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
  12. [N 12]
    distance error: 0.00013 AU. The asteroid is unconfirmed and will likely never receive a provisional designation. The asteroid may have impacted Earth.
  13. [N 13]
    distance error: 0.00020 AU. The asteroid is unconfirmed and will likely never receive a provisional designation.
  14. [N 14]
    distance error: 0.00000085 AU. The asteroid is unconfirmed and will likely never receive a provisional designation.
  15. [N 15]
    distance error: 0.00032 AU. The asteroid is unconfirmed and will likely never receive a provisional designation.
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Timeline of close approaches less than one lunar distance from the Moon

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The number of asteroids listed here are significantly less than those of asteroids that approach Earth for several reasons. Asteroids that approach Earth not only move faster, but are brighter and are easier to detect with modern surveys because:

  • Asteroids that come closer to Earth are a higher priority to confirm, and only confirmed asteroids are listed with a lunocentric approach distance.
  • Those that closely approach the Moon are frequently lost in its glare, making them harder to confirm. They are similarly hard to discover during the new moon, when the Moon is too close to the Sun to detect asteroids while they are near the Moon.

These factors severely limit the amount of Moon-approaching asteroids, to a level many times lower than the asteroids detected passing as close to Earth.

More information Date ofclosest approach, Object ...

Notes

  1. [N 1]
    Distance from the center of the Moon to the center of the object. The Moon has a radius of approximately 1,740 km.
  2. [N 2]
    Distance error: 0.0010 AU, approach range: 0.54 to 1.32 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
  3. [N 3]
    the asteroid is unconfirmed and will likely never receive a provisional designation.
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Additional examples

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Radar image of 2016 AZ8 and its satellite during close approach in January 2019
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Moshup and its satellite Squannit imaged by the VLT during closest approach in May 2019

An example list of near-Earth asteroids that passed more than 1 lunar distance (384,400 km or 0.00256 AU) from Earth in 2019.

More information Object, Size meters ...

Notes

  1. [N 1]
    2012 KT12 could have potentially passed less than 1 lunar distance to Earth, but the chances were fairly low and as such it was not listed in the main table unless followup observations confirmed that it would pass less than 1 LD from Earth. It was recovered on 2 May 2019.

Virtual impactors

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Listed are asteroids that are included on the Sentry Risk Table because they have short observation arcs with poorly constrained orbits and have a chance of striking Earth in 2019. Given a short observation arc, many different orbits fit the observed data. These objects could be millions if not billions of kilometers from Earth on the date of a low probability virtual impactor. For example, 2008 SH148 is expected to be 5.3 AU (800 million km) from Earth in October 2019 around the time of the virtual impact.

Cumulatively among the asteroids listed below, there is a roughly 1 in 16,500 chance that any of the asteroids will impact Earth in 2019. Most of this comes from asteroid 2006 QV89 which formerly had a 1 in 20,000 chance of impact on 9 September 2019, but the impact was ruled out in August.

Also included are asteroids discovered before impact and exceptionally massive fireballs with either an equivalent yield of more than 1 kiloton of TNT or an estimated size of more than 3 meters.

More information Date, Object ...

Notes

  1. [N 1]
    This is a measurement of how far off of the "best fit" orbit the asteroid would have to have for it to hit at this time. Further values from 0 mean that the measured positions of the asteroid used to calculate its orbit would need to be highly inaccurate for it to hit Earth. For reference, 1.0/-1.0=31.7% odds the observations would be this inaccurate, 2.0/-2.0=4.6% odds, 3.0/-3.0=0.27% odds.
  2. [N 2]
    2014 HN198 was ruled out as a potential impactor after further observations from Cerro Tololo, improving the orbit enough to determine that it won't hit Earth.
  3. [N 3]
    2010 DG77 has a cumulative probability of 1 in 195,000,000 (Palermo scale -6.89) of impacting Earth in 2019.
  4. [N 4]
    This listing is compiled from 3 separate virtual impacts at the exact same time, and simply spread out by several sigma. The probabilities are updated to reflect the duplicated listings.
  5. [N 5]
    2008 EL68 has a cumulative probability of 1 in 703,000 (Palermo scale -6.14) of impacting Earth in 2019.
  6. [N 6]
    2016 AZ193 has a cumulative probability of 1 in 223,000,000 (Palermo scale -8.00) of impacting Earth in 2019.
  7. [N 7]
    2010 XC has a cumulative probability of 1 in 16,600,000 (Palermo scale -7.90) of impacting Earth in 2019.
  8. [N 8]
    2015 HV182 has a cumulative probability of 1 in 140,000,000 (Palermo scale -5.39) of impacting Earth in 2019.
  9. [N 9]
    2009 VZ39 has a cumulative probability of 1 in 16,200,000 (Palermo scale -7.53) of impacting Earth in 2019.
  10. [N 10]
    2011 CF66 has a cumulative probability of 1 in 50,800,000 (Palermo scale -7.75) of impacting Earth in 2019.
  11. [N 11]
    2008 EK68 has a cumulative probability of 1 in 47,600,000 (Palermo scale -8.08) of impacting Earth in 2019.
  12. [N 12]
    2008 EM68 has a cumulative probability of 1 in 427,000 (Palermo scale -5.42) of impacting Earth in 2019.
  13. [N 13]
    2014 HG196 has a cumulative probability of 1 in 539,000,000 (Palermo scale -8.09) of impacting Earth in 2019.
  14. [N 14]
    2008 US has a cumulative probability of 1 in 698,000 (Palermo scale -7.38) of impacting Earth in 2019.
  15. [N 15]
    2014 LY21 has a cumulative probability of 1 in 213,000 (Palermo scale -5.39) of impacting Earth in 2019.
  16. [N 16]
    This listing is compiled from 16 separate virtual impacts at the exact same time, and simply spread out by several sigma. The probabilities are updated to reflect the duplicated listings.
  17. [N 17]
    2014 HR197 has a cumulative probability of 1 in 399,000,000 (Palermo scale -8.16) of impacting Earth in 2019.
  18. [N 18]
    2010 VP139 has a cumulative probability of 1 in 5,950,000 (Palermo scale -7.56) of impacting Earth in 2019.
  19. [N 19]
    2008 VS4 has a cumulative probability of 1 in 50,100,000 (Palermo scale -6.30) of impacting Earth in 2019.
  20. [N 20]
    2008 XK has a cumulative probability of 1 in 101,000,000 (Palermo scale -7.68) of impacting Earth in 2019.
  21. [N 21]
    2017 WF30 has a cumulative probability of 1 in 196,000,000 (Palermo scale -7.67) of impacting Earth in 2019.
  22. [N 22]
    2014 JT79 had a cumulative probability of 1 in 44,800,000 (Palermo scale -7.56) of impacting Earth in 2019. It was ruled out as a potential impactor after further observations from Cerro Tololo, improving the orbit enough to determine that it won't hit Earth.
  23. [N 23]
    2005 TM173 has a cumulative probability of 1 in 338,000,000 (Palermo scale -6.67) of impacting Earth in 2019.
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