2019 flyby
- 5 minute markers of trajectory above the earth near closest approach
| 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 | |
Mean diameter | 1–2 m [4] [5] [6] |
| Mass | 2800 kg (est.) [4] |
| 32.0 [1] [3] | |
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]
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.
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.
There is a small chance the asteroid will pass 0.0001 AU (15,000 km) from Mars on 26 October 2023. [3] There is also a 1 in 3 million chance the asteroid will impact Earth on 1 November 2111. [4]
| Asteroid | Date | Distance from surface of Earth | Uncertainty in approach distance | Observation arc | Reference |
|---|---|---|---|---|---|
| 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 |
2010 GA6 is a micro-asteroid on an eccentric orbit, classified as a near-Earth object of the Apollo group. It was first observed on 5 April 2010, by astronomers of the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, United States, four days before a close approach to Earth at 1.1 lunar distances on 9 April 2010. It has not been observed since.
(276033) 2002 AJ129, provisional designation 2002 AJ129, is a Mercury-crossing asteroid. It has the ninth-smallest perihelion of all numbered asteroids, after asteroids such as 2000 BD19, 2004 UL, and 2008 XM. It makes close approaches to all of the inner planets and asteroid 4 Vesta. The asteroid is estimated to be between 0.5–1.2 kilometers (0.3–0.7 mi) across. In January 2018 there was much media hype about this asteroid being classified as a potentially hazardous asteroid, although there is no known threat of an impact for hundreds if not thousands of years. The media has compared the size of the asteroid to the Burj Khalifa in Dubai.
2012 KP24 (also written 2012 KP24) is a Chelyabinsk-sized near-Earth asteroid with an observation arc of only 5 days and has a modestly determined orbit for an object of its size. Around 31 May 2023 ±3 days it will pass between 0.19–24 lunar distances (73,000–9,200,000 km) from Earth. Nominally the asteroid is expected to pass 0.026 AU (3,900,000 km; 10 LD) from Earth and brighten to around apparent magnitude 21.6.
2013 TV135 is an Apollo near-Earth asteroid estimated to have a diameter of 450 meters (1,480 ft). On 16 September 2013, it passed about 0.0448 AU (6,700,000 km; 4,160,000 mi) from Earth. On 20 September 2013, it came to perihelion (closest approach to the Sun). The asteroid was discovered on 12 October 2013 by Ukrainian amateur astronomer Gennadiy Borisov with a custom 0.2-meter (7.9 in) telescope using images dating back to 8 October 2013. It was rated level 1 on the Torino Scale from 16 October 2013 until JPL solution 26 on 3 November 2013. It reached a Palermo Technical Impact Hazard Scale rating of -0.73. It was removed from the JPL Sentry Risk Table on 8 November 2013 using JPL solution 32 with an observation arc of 27 days.
2009 RR micro-asteroid, classified as near-Earth object of the Apollo group. It was discovered on 11 September 2009 by the Catalina Sky Survey at an apparent magnitude of 19.5 using a 0.68-meter (27 in) Schmidt–Cassegrain telescope. 2009 RR was the only asteroid discovered before 2014 that was predicted to potentially pass inside the orbit of the Moon during 2014. The asteroid has an estimated diameter of 26 meters (85 ft) and is listed on the Sentry Risk Table. It is not large enough to qualify as a potentially hazardous object.
2005 HC4 is the asteroid with the smallest known perihelion of any known object orbiting the Sun (except sungrazing comets). Its extreme orbital eccentricity brings it to within 0.071 AU of the Sun (23% of Mercury's perihelion) and takes it as far as 3.562 AU from the Sun (well beyond the orbit of Mars). Due to its very small perihelion and comparably large aphelion, 2005 HC4 achieves the fastest speed of any known asteroid bound to the Solar System with a velocity of 157 km/s (565,000 km/h; 351,000 mi/h) at perihelion (there are comets, however, which obtain much higher speeds).
2015 TB145 is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 650 meters (2,000 feet) in diameter. It safely passed 1.27 lunar distances from Earth on 31 October 2015 at 17:01 UTC, and passed by Earth again in November 2018.
2013 TX68 is an Apollo asteroid and near-Earth object discovered on 6 October 2013 by the Catalina Sky Survey, during which it was near a close approach of 5.4 Lunar distances (LD) from the Earth. The asteroid only has a 10-day observation arc which makes long-term predictions of its position less certain. It was observed for three days as it approached Earth in the night sky starting with the sixth of October, 2013. Then it became unobservable by being between the Earth and the Sun, then not recovered due to its small size and dimness. Precovery images by Pan-STARRS from 29 September 2013 were announced on 11 February 2016 that extended the observation arc to 10 days. It was removed from the Sentry Risk Table on 11 February 2016, so there is no risk of impact from this object for the next hundred years or more. The asteroid was last observed on 9 October 2013.
2018 CC is a micro-asteroid, classified as a near-Earth object of the Apollo group, approximately 20 meters (70 ft) in diameter. Its official first observation was made by the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, United States, on 4 February 2018. Two days later, the asteroid crossed the orbit of the Moon and made a very close approach to Earth.
2006 QV89 (also written 2006 QV89) is an Apollo near-Earth asteroid roughly 30 meters (100 feet) in diameter. It was discovered on 29 August 2006 when the asteroid was about 0.03 AU (4,500,000 km; 2,800,000 mi) from Earth and had a solar elongation of 150 degrees.
2020 LD is an Apollo near-Earth asteroid roughly 140 meters in diameter. It was discovered on 7 June 2020 when the asteroid was about 0.03 AU from Earth and had a solar elongation of 154 degrees. The glare of the Sun had masked the approach of the asteroid since November 2019. The asteroid passed closest approach to Earth on 5 June 2020 at a distance of 0.002 AU. The close approach distance is now known with an accuracy of roughly ± 1000 km. This is the largest asteroid to pass closer than the Moon this year and possibly the largest since (308635) 2005 YU55 in November 2011. The asteroid makes close approaches to Mercury, Venus, Earth, and Mars. It will be brighter than apparent magnitude 24 until 18 July 2020.
2019 BE5 is a sub-kilometer near-Earth asteroid classified under the Aten group. It was discovered on 31 January 2019, by the Zwicky Transient Facility at the Palomar Observatory. The asteroid was discovered one day after it had made a close approach to Earth from a distance of 0.00784 AU (1.173 million km; 3.05 LD).
2020 VT4 is a tiny near-Earth asteroid that passed 370 km (230 mi) above Earth's surface on 13 November 2020 at 17:20 UTC. The asteroid was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey at the Mauna Loa Observatory fifteen hours after its closest approach to Earth. The Earth encounter perturbed the asteroid's trajectory from an Earth-crossing Apollo-type orbit to an Aten-type orbit, subsequently reducing the asteroid's heliocentric orbital period from 1.5 years to 0.86 years.
2020 AP1 is an Apollo near-Earth object roughly 5 meters (20 feet) in diameter. On 2 January 2020 it passed 0.00218 AU (326 thousand km; 0.85 LD) from Earth. With a short 1-day observation arc it was roughly expected to pass about 0.01 AU (1.5 million km; 3.9 LD) from Earth on 7 January 2022, but with an uncertainty of ±8 days for the close approach date it could have passed significantly closer or further.
2021 AV7 is a near-Earth asteroid of the Apollo group, discovered by astronomers Alain Maury and G. Attard at San Pedro de Atacama, Chile on 15 January 2021. With an estimated diameter of 450–1,000 m (1,480–3,280 ft), it is considered a potentially hazardous asteroid. It has a highly elliptical orbit that brings it within Earth's orbit. Although its nominal orbit has a small minimum orbit intersection distance around 70,000 km (43,000 mi) from Earth's orbital path, the asteroid does not make any close approaches within 0.2 astronomical units (30×106 km; 19×106 mi) over the next 100 years.
2020 SL1 is a near-Earth asteroid of the Apollo group, discovered by the Pan-STARRS 1 survey at Haleakala Observatory, Hawaii on 18 September 2020. With an estimated diameter of 0.9–2.0 km (0.56–1.24 mi), it is the largest potentially hazardous asteroid discovered in 2020.
2020 SW is a tiny near-Earth asteroid discovered by the Mount Lemmon Survey on 18 September 2020, six days before it made its closest approach to Earth. The asteroid passed within 21,600 kilometres (13,400 mi) from Earth's surface on 24 September 2020 11:13 UT, within the geostationary altitude of 36,000 kilometres (22,000 mi). The encounter with Earth perturbed the asteroid's heliocentric trajectory from an Apollo-type orbit to an Aten-type orbit with a semi-major axis within one astronomical unit from the Sun. As a result, the asteroid will not make any close approaches to Earth within 0.01 astronomical units (4 LD) in the next 200 years.
2009 JF1 is a small near-Earth object that should have passed within 0.3 AU (45 million km) of Earth in 2022. On 5 February 2022 the 2009 observations were remeasured greatly reducing the odds of an impact. On 6 May 2022 it had a 1-in-140,000 chance of impacting Earth. It is estimated to be 10-meters in diameter which would make it smaller than the Chelyabinsk meteor. It has a very short observation arc of 1.2 days and has not been observed since 2009. On 6 May 2022 it was nominally expected to be 0.2 AU (30 million km) from Earth but has an uncertainty region of ±23 million km (0.15 AU). The nominal Earth approach was 15 May 2022 and would have had the asteroid only brightening to apparent magnitude 26 which would have made it too faint for automated surveys to detect. With a Palermo scale rating of -4.41, the odds of impact were 26000 times less than the background hazard level for an asteroid of this size.
2021 TP21 is an Apophis-sized asteroid that was discovered on 11 October 2021 when it was 0.5 AU (75 million km) from Earth. This potentially hazardous asteroid (PHA) spends most or its orbit closer to 4 AU (600 million km) from the Sun as objects orbit more slowly when near aphelion (furthest distance from the Sun). 2021 TP21 was rated with a Torino scale of 1 from 31 October 2021 to 4 November 2021 for a potential impact on 27 March 2081. As the observation arc became longer the nominal distance from Earth became further on the potential impact date.
2022 YO1 is a small and harmless near-Earth object that will pass within 0.014 AU (2.1 million km) of Earth around 17 December 2024. At 17 December 2024 06:14 UT it has a 0.23% (1-in-430) chance of impacting Earth. It is estimated to be 3-meters in diameter which would make an impact comparable to 2008 TC3. It has a very short observation arc of 0.4 days and was first imaged on 17 December 2022 07:07 when it was 0.004 AU (600 thousand km) from Earth.
