Discovery [1] | |
---|---|
Discovered by | Spacewatch |
Discovery site | Kitt Peak National Obs. |
Discovery date | 24 February 2009 |
Designations | |
(410777) 2009 FD | |
2009 FD | |
Orbital characteristics [1] | |
Epoch 3 July 2013 (JD 2456476.5) | |
Uncertainty parameter 0 | |
Observation arc | 6.77 yr (2,471 days) |
Aphelion | 1.7361 AU |
Perihelion | 0.5896 AU |
1.1629 AU | |
Eccentricity | 0.4929 |
1.25 yr (458 days) | |
98.579° | |
0° 47m 9.6s / day | |
Inclination | 3.1366° |
9.5523° | |
281.24° | |
Known satellites | 1 [3] |
Earth MOID | 0.0025 AU (1 LD) |
Physical characteristics | |
Mean diameter |
|
Mass | 8.3×1010 kg (assumed) [7] |
| |
22.1 [1] [4] | |
(410777) 2009 FD is a carbonaceous sub-kilometer asteroid and binary system, [6] [3] classified as near-Earth object and potentially hazardous asteroid of the Apollo group, discovered on 24 February 2009 by astronomers of the Spacewatch program at Kitt Peak National Observatory near Tucson, Arizona, in the United States. [2]
Until 2019, the asteroid's modelled orbit placed it at risk of a possible future collision with Earth in 2185. With a Palermo Technical Impact Hazard Scale rating of -0.44, it had the fifth highest impact threat [lower-alpha 2] of all known asteroids based on its estimated diameter, kinetic yield, impact probability, and time interval. [12] Observations to 2019 extended the observation arc by four years and detected a favourable Yarkovsky effect, which ruled out impact in 2185. [13] Using observations from 16 November 2020, the asteroid was removed from the Sentry risk table on 19 November 2020.
2009 FD was initially announced as discovered on 16 March 2009 by La Sagra Sky Survey. [14] Because there were previous observations found in images taken by the Spacewatch survey some 3 weeks prior, on 24 February 2009, the Minor Planet Center assigned the discovery credit to Spacewatch under the discovery assignment rules. [15] [2] 2009 FD made a close pass to Earth on 27 March 2009 at a distance of 0.004172 AU (624,100 km ; 387,800 mi ) [16] [17] and another on 24 October 2010 at 0.0702 AU. [16] 2009 FD was recovered at apparent magnitude 23 [lower-alpha 3] on 30 November 2013 by Cerro Paranal Observatory, [2] several months before the close approach of April 2014 when it passed 0.1 AU from Earth. [16] It brightened to roughly apparent magnitude 19.3 around mid-March 2014. [18] One radar Doppler observation of 2009 FD was made in 2014. [1] The October–November 2015 Earth approach was studied by the Goldstone Deep Space Network. [19]
NASA's Near Earth Program originally estimated its size to be 130 metres in diameter based on an assumed albedo of 0.15. [20] This gave it an estimated mass of around 2,800,000 tonnes. [20] But work by Amy Mainzer using NEOWISE data in 2014 showed that it could be as large as 472 metres with an albedo as low as 0.01. [1] [5] Because 2009 FD (K09F00D) was only detected in two (W1+W2) of the four wavelengths the suspected NEOWISE diameter is more of an upper limit. [5] Radar observations in 2015 showed it to be a binary asteroid. [6] The primary is 120–180 meters in diameter and the secondary is 60–120 meters in diameter. [6]
The JPL Small-Body Database shows that 2009 FD will make two very close approaches in the late 22nd century, in 2185 and 2190. As of 2016, the approach of 29 March 2185 had a 1 in 710 chance of impacting Earth. [7] The nominal 2185 Earth approach distance was 0.009 AU (1,300,000 km; 840,000 mi). [16] Orbit determination for 2190 is complicated by the 2185 close approach. [16] The precise distance that it will pass from Earth and the Moon on 29 March 2185 will determine the 30 March 2190 distance. 2009 FD should pass closer to the Moon than Earth on 29 March 2185. [16] An impact by 2009 FD would cause severe devastation to a large region or tsunamis of significant size. [21]
In January 2011, near-Earth asteroid 2009 FD (with observations through 7 December 2010) was listed on the JPL Sentry Risk Table with a 1 in 435 chance of impacting Earth on 29 March 2185. [20] In 2014 (with observations through 5 February 2014, creating an observation arc of 1807 days) the potential 2185 impact was ruled out. [22] Using the 2014 observations, the Yarkovsky effect has become more significant than the position uncertainties. [23] [11] [24] The Yarkovsky effect has resulted in the 2185 virtual impactor returning. While 2009 FD was estimated to be 470 meters in diameter, it was rated −0.40 on the Palermo Scale, placing it higher on the Sentry Risk Table than any other known object at the time. [12]
On 14 June 2019, Alessio Del Vigna and colleagues published a new analysis, which incorporates astrometry taken in 2019. Using both JPL's Sentry as well as NEODyS's CLOMON-2 system, the new data allowed a 4-sigma detection of the Yarkovsky effect at (+3.6±0.9)×10−3 AU/Myr . The 2019 observations extended the observation arc from six years to ten years. This ruled out the 2185 impact possibility, leaving the potential impact in 2190 as the only theoretically possible impact until 2250, at a very low probability of 1 in 100 million. [13] On 19 November 2020, the asteroid was finally completely removed from the sentry risk table as all possible impacts, including 2190 and 2250, were ruled out.
The Torino scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. It is intended as a communication tool for astronomers and the public to assess the seriousness of collision predictions, by combining probability statistics and known kinetic damage potentials into a single threat value. The Palermo Technical Impact Hazard Scale is a similar, but more complex scale.
Sentry is a highly automated impact prediction system operated by the JPL Center for NEO Studies (CNEOS) since 2002. It continually monitors the most up-to-date asteroid catalog for possibilities of future impact with Earth over the next 100+ years. Whenever a potential impact is detected it will be analyzed and the results immediately published by the Center for Near-Earth Object Studies. However, several weeks of optical data are not enough to conclusively identify an impact years in the future. By contrast, eliminating an entry on the risk page is a negative prediction.
(292220) 2006 SU49, provisional designation 2006 SU49, is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group that had a small chance of impacting Earth in 2029.
2007 VK184 is a sub-kilometer asteroid, classified as a near-Earth object of the Apollo group, and estimated to be approximately 130 meters (430 ft) in diameter. It was listed on the Sentry Risk Table with a Torino Scale rating of 1 for a potential impactor in June 2048. It was removed from the Sentry Risk Table on 28 March 2014.
2010 AU118 (also written 2010 AU118) is a potential Amor near-Earth asteroid with an observation arc of only 1.4 days and thus a poorly determined orbit. It was announced on 27 May 2010 based on images taken by the Wide-field Infrared Survey Explorer (WISE) on 13–15 January 2010. It was removed from the Sentry Risk Table on 14 June 2014 as a result of an update to the Sentry software. Another software update restored it to the Sentry Risk Table in 2017. It was again removed from the sentry list on 3 October 2018.
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.
2014 DX110 is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group, approximately 30 meters in diameter. It passed less than 1 lunar distance from Earth on 5 March 2014. With an absolute magnitude of 25.7, this asteroid is potentially the largest asteroid to come inside the orbit of the Moon since 2013 PJ10 on 4 August 2013. The close approach was webcast live by Slooh and Virtual Telescope.
2012 TC4 is a tumbling micro-asteroid classified as a bright near-Earth object of the Apollo group, approximately 10 meters (30 feet) in diameter. It was first observed by Pan-STARRS at Haleakala Observatory on the Hawaiian island of Maui, in the United States. As of 1 October 2017, it had a small Earth minimum orbital intersection distance of 0.000149 AU (22,300 km). On 12 October 2017, it passed Earth at 0.00033524 AU (50,151 km). The asteroid was removed from the Sentry Risk Table on 16 October 2017 and with a 5-year observation arc has a well-known orbit. For example, on the previously risk-listed date of 12 October 2022, it is now known that the asteroid will be more than 3 AU (450 million km) from Earth.
2012 FN is an Apollo asteroid and a near-Earth object that has a 1 in 4 billion chance of impacting Earth on 7 March 2113. It is estimated to be 5 meters in diameter, which means that it poses no threat if it impacts Earth. An impact would have the kinetic energy of about 3 kt of TNT, and would probably result in an air burst in the upper atmosphere. It is the least threatening asteroid listed on the Sentry Risk Table. The very short observation arc of only 3 hours results in a very poorly constrained orbit, and it could just as easily be 2 AU from Earth on 7 March 2113.
2014 OO6 (also written 2014 OO6) is an Apollo near-Earth asteroid discovered in 2014 and was the most dangerous one discovered in 2014 that remained on the Sentry Risk Table as of early December 2014. The asteroid is estimated to be roughly 75 meters (246 ft) in diameter and had a 1 in 83,000 chance of impacting Earth on 11 January 2051. However, the nominal best-fit orbit shows that 2014 OO6 will be 1.5 AU (220,000,000 km; 140,000,000 mi) from Earth on 11 January 2051.
2007 VE191 is a sub-kilometer asteroid, classified as near-Earth asteroid of the Apollo group that was listed on the Sentry Risk Table.
2014 XL7 is a near-Earth object and Apollo asteroid, approximately 230 meters (750 feet) in diameter. It was the most dangerous potentially hazardous asteroid on Sentry Risk Table upon its discovery by the Mount Lemmon Survey in December 2014. At the time, the asteroid had a cumulative 1 in 83000 chance of impacting Earth on 4–5 June between the years 2048 and 2084. After the object's observation arc had been extended to 35 days, it was removed from the Sentry Risk Table on 15 January 2015. Since then the asteroid's orbit has been secured. Although it has an Earth minimum orbit intersection distance of less than one lunar distance, there are no projected close encounters with Earth in the foreseeable future, with its closest passage to occur in May 2046, still millions of kilometers away.
2015 AZ43 (also written 2015 AZ43) is an Apollo near-Earth asteroid roughly 70 meters in diameter. On 10 February 2015 with a 29.5-day observation arc, it showed a 1 in 5,880 chance of impacting Earth on 27 February 2107. However, the NEODyS nominal best-fit orbit shows that 2015 AZ43 will be 2.8 AU (420,000,000 km; 260,000,000 mi) from Earth on 27 February 2107. A (non-impacting) Earth close approach in 2056 makes future trajectories diverge. It was removed from the JPL Sentry Risk Table on 23 February 2015 using JPL solution 26 with an observation arc of 40 days that included radar data.
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.
2011 ES4 (also written 2011 ES4) is an Apollo near-Earth asteroid roughly 22–49 meters (72–160 feet) in diameter. It was first observed on 2 March 2011 when the asteroid was about 0.054 AU (8,100,000 km; 5,000,000 mi) from Earth and had a solar elongation of 159 degrees. It passed closest approach to Earth on 13 March 2011. Before the 2020 approach, the asteroid had a short observation arc of 4 days and had not been observed since March 2011. The asteroid was expected to pass within 1 lunar distance of Earth in early September 2020, but did not. There was no risk of a 2020 impact because the line of variation (LOV) did not pass through where Earth would be, and the closest possible 2020 Earth approach was about 0.00047 AU (70,000 km; 44,000 mi). One line of variation showed the asteroid passing closest to Earth on 5 September 2020 at 0.06 AU (9,000,000 km; 5,600,000 mi) with a magnitude of 23, which would place it near the limiting magnitude of even the best automated astronomical surveys.
2018 VP1 is an Apollo near-Earth asteroid roughly 2 meters (7 feet) in diameter. The asteroid had a 0.41% chance (1 in 240) of impacting Earth on 2 November 2020 01:12 UT. It was discovered on 3 November 2018 when it was about 0.003 AU (450,000 km; 280,000 mi) from Earth and had a solar elongation of 165 degrees. The asteroid has a short 12.9 day observation arc. It was last observed on 16 November 2018 by the European Southern Observatory Very Large Telescope at apparent magnitude 26 pushing the telescope close to the limiting magnitude.
1979 XB is a lost asteroid with a short observation arc of 3.9 days that cannot be recovered with targeted observations and awaits serendipitous survey observations. It is classified as a near-Earth object and potentially hazardous asteroid of the Apollo group and is estimated to be 660 meters in diameter. The unnumbered minor planet has a poorly constrained orbit and has not been observed in 40 years. It has been listed on the Sentry Risk Table since the list started in 2002. With a cumulative Palermo Technical Impact Hazard Scale of −2.72, the poorly known orbit and assumed size place 1979 XB third on an unconstrained listing of the Sentry Risk Table.
2020 VV is an Apollo near-Earth asteroid roughly 12 meters in diameter. On 20 November 2020, the asteroid had a 4.4% chance of impacting Earth on 12 October 2033 11:43 UT. As of mid-December 2020, the asteroid has a modest 61 day observation arc. The nominal Earth approach is on 17 October 2033 at a distance of 0.009 AU, but the line of variations (LOV) is only known with an accuracy of ±22 hours. The line of variations allows the asteroid to come as close as 0.006 AU or pass as far away as 0.01 AU. With a diameter range of 10–22 meters the asteroid could be as large as the Chelyabinsk meteor.
2022 AE1 is a Tunguska event-sized asteroid, classified as a near-Earth object of the Apollo group, approximately 70 meters (230 feet) in diameter. It was discovered by the Mount Lemmon Survey on 6 January 2022, when it was 0.09 AU (13 million km) from Earth. On 9 January 2022 with an observation arc of 3 days, it was rated with a Torino scale of 1 for a virtual impactor on 4 July 2023 16:28 UTC. Nominal approach is expected to occur 1 July 2023 01:13 ± 1 day. With a Palermo scale rating of as high as –0.66 at the European Space Agency on 11 January 2022, the odds of impact peaked at about 4.6 times less than the background hazard level. NEODyS was the first risk-page to drop to Torino scale 0 on 12 January 2022 followed by ESA on 13 January 2022, but by January 14 both returned to Torino scale 1. On 14 January 2022 the waxing gibbous moon was as little as 3 degrees from the asteroid delaying observations of the asteroid from January 12–19. On 20 January 2022 with a 16-day observation arc, using JPL #11 the Sentry Risk Table dropped the asteroid to Torino scale 0 and then later that day JPL #12 resulted in it being removed from the risk table.