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(481482) 2007 CA19 is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It led the impact hazard list, with a Torino Scale impact risk value of 1, for one week, ending on February 19, 2007. Before and after 2007 CA19, 99942 Apophis was the object with the highest Palermo Scale rating. With an observation arc of 4.8 days, it had a Palermo Scale of −0.88.
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.
(164207) 2004 GU9 is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It will be a quasi-satellite of Earth until around 2600.
(471240) 2011 BT15, provisional designation 2011 BT15, is a stony, sub-kilometer sized asteroid and fast rotator, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group. It had been one of the objects with the highest impact threat on the Palermo Technical Impact Hazard Scale.
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.
2008 CK70 (also written 2008 CK70) is an Apollo near-Earth asteroid. In 2013 it had the 7th highest impact threat on the Palermo Technical Impact Hazard Scale. It was discovered on 9 February 2008 by Lincoln Near-Earth Asteroid Research (LINEAR) at an apparent magnitude of 19 using a 1.0-meter (39 in) reflecting telescope. It has an estimated diameter of 31 meters (102 ft) and is not large enough to qualify as a potentially hazardous object. Ten precovery images from January 2008 have been located. It was removed from the Sentry Risk Table on 21 December 2013. It may be possible to recover the asteroid in late September 2017, but it will have an apparent magnitude of about 22.
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 UR116, also known as 2008 XB, is an eccentric sub-kilometer asteroid, categorized as a near-Earth object and potentially hazardous asteroid of the Apollo group with a diameter of approximately 400 meters (1,300 ft). It was first observed on 1 December 2008, by the Mount Lemmon Survey at Mount Lemmon Observatory in Arizona, United States.
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.
2012 TV is a near-Earth Apollo asteroid with an estimated diameter of 30 metres (98 ft). Its closest approach to the Earth was on October 7, 2012 with a distance of 0.0017 astronomical units. It also approached the Moon an hour earlier with a distance of 0.0028 astronomical units. With a short observation arc of 1.8 days, the asteroid is listed on the Sentry Risk Table and has a 1:500,000 chance of impacting Earth on April 2, 2081.
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.
(415029) 2011 UL21, provisional designation 2011 UL21, is an Apollo class potentially hazardous asteroid discovered on October 17, 2011, by the Catalina Sky Survey project. The asteroid is estimated to have a diameter of 2.5 kilometres (1.6 mi). It was rated at Torino Scale 1 on October 27, 2011, with an observation arc of 9.6 days.
2018 XB4 (also written 2018 XB4) is an Apollo near-Earth asteroid roughly 53 meters (170 feet) in diameter. It was discovered on 13 December 2018 when the asteroid was about 0.125 AU (18,700,000 km; 11,600,000 mi) from Earth and had a solar elongation of 146°. It passed closest approach to Earth on 1 January 2019. Of the asteroids discovered in 2018, it had the highest Palermo scale rating at –3.6. In mid-2019 it was recovered which extended the observation arc to 177 days and was removed from the Sentry Risk Table on 12 June 2019. It is now known that on 22 June 2092 the asteroid will pass about 0.033±0.015 AU from Earth.
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 XR is an Apollo near-Earth object and potentially hazardous asteroid roughly 390 meters in diameter. With a 5-day observation arc it was briefly listed as having a 1 in 11,000 chance of impacting Earth on 1 December 2028 placing it at the top of the Sentry Risk Table with a Palermo scale rating of -0.70.
2023 GQ2 is an asteroid roughly 400 meters in diameter, classified as a near-Earth object and potentially hazardous object of the Apollo group. It was first discovered on 12 April 2023, when it was 1.3 AU (190 million km) from Earth, with the Bok Telescope at Kitt Peak National Observatory. On 19 April 2023, with an observation arc of 6.7 days, it was rated 1 on the Torino scale for a virtual impactor on 16 November 2028 at 00:58 UTC. When it had a Palermo scale rating of –0.70, the odds of impact were about 5 times less than the background hazard level and this gave the asteroid one of the highest Palermo scale ratings ever issued. On 20 April 2023 precovery images from May 2019 were announced extending the observation arc to 3.9 years, and the 2028 virtual impactor was removed from the Sentry Risk Table. It is now known the nominal approach will safely occur about 13 hours after the impact scenario on 16 November 2028 13:36 ± 40 minutes.
References
- 1 2 3 4 "JPL Small-Body Database Browser: (2012 FN)" (last observation: 2012-03-17; arc: 3 hours; uncertainty: 9). Jet Propulsion Laboratory. Retrieved 1 April 2016.
- 1 2 3 NASA JPL. "2012 FN Impact Risk". Archived from the original on 31 July 2014. Retrieved 25 October 2014.
- ↑ Sentry Risk Table (NASA JPL)
- ↑ "2012FN Ephemerides for 6-8 March 2113". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 25 October 2014.
