2019 UN13
3rd closest non-impacting Earth approach
From Wikipedia, the free encyclopedia
2019 UN13 is a small near-Earth asteroid roughly 1–2 meters in diameter. Even though the asteroid was in the night sky for months, it was fainter than the sky survey limit of apparent magnitude 24 until 29 October 2019 when the asteroid was two million km from Earth.[7] It was discovered on October 31, 2019, passing 6,200 km above Earth's surface.[8][9]
| Discovery[1] | |
|---|---|
| Discovered by | CSS (Teddy Pruyne) |
| Discovery site | Catalina Stn. |
| Discovery date | 31 October 2019 (first observed only) |
| Designations | |
| 2019 UN13 | |
| C0PPEV1[2] | |
| NEO · Aten[1][3] | |
| Orbital characteristics[3] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 7 | |
| Observation arc | 3.7 hours[1] (18 observations) |
| Aphelion | 1.3301 AU (2.06 AU after passage) |
| Perihelion | 0.6463 AU |
| 0.9882 AU | |
| Eccentricity | 0.3460 |
| 359 days | |
| 100.74° | |
| 1° 0m 12.24s / day | |
| Inclination | 1.4925° |
| 217.58° | |
| 291.05° | |
| Earth MOID | 0.000005 AU (700 km) |
| Physical characteristics | |
| 1–2 m[4][5][6] | |
| Mass | 2800 kg (est.)[4] |
| 32.0[1][3] | |
2020 QG and 2011 CQ1 are the only asteroids known where the nominal orbit passed closer to the surface of Earth.[6] Other asteroids that passed very close to Earth include 2004 FU162, 2018 UA, and 2019 AS5.
An impact by 2019 UN13 would be less significant than the 2018 LA impact.
2019 flyby
- 5 minute markers of trajectory above the earth near closest approach
Orbit changes
The close approach to Earth lifted the asteroid's aphelion point (furthest distance from the Sun) from 1.33 AU (inside the orbit of Mars) to 2.06 AU (near the edge of the inner asteroid belt). The approach changed the orbit from an Aten asteroid with a semi-major axis less than 1 AU to an Apollo asteroid with a semi-major axis greater than that of the Earth (> 1 AU).
| 2019[3] | 2020 | |
|---|---|---|
| Orbit type | Aten | Apollo |
| Perihelion (closest distance to the Sun) | 0.64 AU | 0.83 AU |
| Semi-major axis (average distance from the Sun) | 0.98 AU | 1.4 AU |
| Aphelion (furthest distance from the Sun) | 1.3 AU | 2.0 AU |
| Orbital period | 358 days | 637 days |
With the new orbit, 2019 UN13 will come to perihelion 0.83 AU from the Sun on 15 December 2019. Without perturbations, the previous orbit would have come to perihelion in January 2020.
Future
See also
| Asteroid | Date | Distance from surface of Earth |
Uncertainty in approach distance |
Observation arc | Reference |
|---|---|---|---|---|---|
| 2025 UC11 | 2025-10-30 12:11 | 237 km | ±11 km | 1 day (41 obs) | data |
| 2020 VT4 | 2020-11-13 17:21 | 368 km | ±11 km | 5 days (34 obs) | data |
| 2020 QG | 2020-08-16 04:09 | 2939 km | ±11 km | 2 days (35 obs) | data |
| 2021 UA1 | 2021-10-25 03:07 | 3049 km | ±10 km | 1 day (22 obs) | data |
| 2023 BU | 2023-01-27 00:29 | 3589 km | ±<1 km | 10 days (231 obs) | data |
| 2011 CQ1 | 2011-02-04 19:39 | 5474 km | ±5 km | 1 day (35 obs) | data |
| 2019 UN13 | 2019-10-31 14:45 | 6235 km | ±189 km | 1 day (16 obs) | data |
| 2008 TS26 | 2008-10-09 03:30 | 6260 km | ±970 km | 1 day (19 obs) | data |
| 2004 FU162 | 2004-03-31 15:35 | 6535 km | ±13000 km | 1 day (4 obs) | data |