List of asteroid close approaches to Earth in 2023

Asteroids which came closer to Earth than the Moon in 2023 by time of discovery

After closest approach: 62 (53.9%)   < 24 hours before: 13 (11.3%)   up to 7 days before: 37 (32.2%)   > one week before: 2 (1.7%)   > 7 weeks before: 0 (0.0%)   > one year before: 1 (0.9%) Other years 2021, 2022, 2023, 2024, 2025

Asteroids which came closer to Earth than the Moon in 2023 by discoverer

G96 Mt. Lemmon Survey: 38 (32.5%)   703 Catalina Sky Survey: 18 (15.4%)   F51 Pan-STARRS 1: 13 (11.1%)   F52 Pan-STARRS 2: 12 (10.3%)   K88 GINOP-KHK, Piszkesteto: 6 (5.1%)   P07 SST, HEH Station: 5 (4.3%)   M22 ATLAS South Africa: 5 (4.3%)   W94 MAP, San Pedro de Atacama: 4 (3.4%)   W68 ATLAS Chile: 3 (2.6%)   L51 Gennadiy Borisov: 2 (1.7%)   I41 Palomar Mountain--ZTF: 1 (0.9%)   950 La Palma: 1 (0.9%)   G03 Capricornus Obs., Csokako: 1 (0.9%)   V00 Kitt Peak-Bok: 1 (0.9%)   I52 Steward Obs., Mt. Lemmon: 1 (0.9%)   N87 Nanshan Station, Xinjiang Obs.: 1 (0.9%)   U74 JPL SynTrack RT 2: 1 (0.9%)   T05 ATLAS-HKO, Haleakala: 4 (3.4%)

Below is the list of asteroids that have come close to Earth in 2023.

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 2023, based on the close approach database of the Center for Near-Earth Object Studies (CNEOS).^[1]

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

The closest approach of Earth by an asteroid in 2023 was that of 2023 BU, an asteroid with a diameter of 3.1–6.9 m (10–23 ft), at 9,967 km (6,193 mi; 6.663×10⁻⁵ AU; 0.02593 LD) from the center of the Earth, or about 3,600 km (2,200 mi) above its surface.^[2] The largest asteroid to pass within 1 LD of Earth in 2023 was 2023 DZ2 at 37–83 m (121–272 ft) in diameter, for an absolute magnitude of 24.3.^[3] The fastest asteroid to pass within 1 LD of Earth in 2023 was 2023 TK₁₅ that passed Earth with a velocity with respect to Earth of 21.95 km/s (49,100 mph),^[4] while the slowest bypass within lunar distance was that of 2023 XQ₁₆ at a velocity with respect to Earth of 3.16 km/s (7,100 mph).^[5]

As most asteroids passing within a lunar distance are less than 40 meters in diameter, they generally are not detected until they are within several million kilometres of Earth. Objects coming from the direction of the Sun may not be publicly announced until a few days after closest approach. For example, 2023 AC₁ was first imaged six hours after closest approach, then confirmed by other observations, but not officially announced until 3.5 days after closest approach.^[6] 2023 MD₄ that approached from the direction of the Sun was not first observed until 3.6 days after closest approach.^{[note 1]} The largest asteroid on this list that is risk–listed is 2023 SM₅ at about 17 meters in diameter with a 3.5-day observation arc and a 1:91000 chance of Earth impact on 24 September 2118.^[7]

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 2023.

This list and relevant databases do not consider impacts as close approaches, thus this list does not include 2023 CX1, 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 2023 which weren't discovered in advance, but were observed visually or recorded by infrasound sensors designed to detect detonation of nuclear devices.^[8]

     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)

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.^[1]

Absolute magnitude H ≥ 30 (smallest)

(size of a person for comparison)

Absolute magnitude 30 > H ≥ 29

Absolute magnitude 29 > H ≥ 28

Absolute magnitude 28 > H ≥ 27

Absolute magnitude 27 > H ≥ 26

Absolute magnitude 26 > H ≥ 25

Absolute magnitude 25 > H (largest)

•   After closest approach: 0 (0.0%)
•   < 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: 1 (50.0%)

Below is an example list of near-Earth asteroids that nominally will pass more than 1 lunar distance (384,400 km or 0.00256 AU) from Earth in 2023. During 2022, over 1,000 asteroids passed within 10 LD (3.8 million km) of Earth.

  Rows highlighted grey indicate a planet or main-belt asteroid

  Rows highlighted green indicate a comet which may have a larger uncertainty region due to non-gravitational forces from outgassing (sublimation).
It is also more difficult to make astrometric measurements of the precise location of the nucleus because it is masked by a fuzzy coma.

  Rows highlighted yellow indicate short arc objects that have not been observed for years and therefore the uncertainty in the approach distance and date are large

  Rows highlighted cyan indicate objects that had a short observation arc with large uncertainties that were recovered and their orbits greatly refined

  Rows highlighted red indicate objects which are risk–listed with a virtual impactor near this date

• List of asteroid close approaches to Earth
• List of asteroid close approaches to Earth in 2022
• List of asteroid close approaches to Earth in 2024
• Asteroid impact prediction