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4769 Castalia is a near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.4 kilometers in diameter and was the first asteroid to be modeled by radar imaging. It was discovered on 9 August 1989, by American astronomer Eleanor Helin (Caltech) on photographic plates taken at Palomar Observatory in California. It is named after Castalia, a nymph in Greek mythology. It is also a Mars- and Venus-crosser asteroid.
2000 SG344 is a small Aten asteroid first observed in 2000. It is assumed to have a diameter of approximately 37 meters (120 feet) – or roughly twice that of the Chelyabinsk meteor – and an assumed mass of 7.1×107 kg (71,000 tonnes), but the size is only known within about a factor 2. It is the largest object known to have a better than 1/1000 chance (0.1%) of impacting Earth and has the fourth highest cumulative Palermo rating at −2.79. The next good chance to observe the object will be in May 2028 when it passes 0.02 AU (3,000,000 km; 1,900,000 mi) from Earth.
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.
1991 BA is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group that was first observed by Spacewatch on 18 January 1991, and passed within 160,000 km (100,000 mi) of Earth. This is a little less than half the distance to the Moon. With a 5-hour observation arc the asteroid has a poorly constrained orbit and is considered lost. It could be a member of the Beta Taurids.
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.
3361 Orpheus is an Apollo asteroid that was discovered on 24 April 1982 by Carlos Torres at Cerro El Roble Astronomical Station. Its eccentric orbit crosses that of Mars and Earth, and approaches Venus as well. From 1900 to 2100 it passes closer than 30 Gm to Venus 11, Earth 33, and Mars 14 times. It passed by Earth at a distance of about 0.03 AU in 1937, 1978, 1982, and 2021 and will again in 2025.
2010 RF12 is a very small asteroid, classified as near-Earth object of the Apollo group, that passed between Earth and the Moon on 8 September 2010, at 21:12 UTC, approaching Earth within 79,000 kilometres (49,000 mi) above Antarctica. The asteroid was discovered by the Mount Lemmon Survey near Tucson, Arizona on 5 September 2010 along with 2010 RX30. Based on a short 7-day observation arc from that apparation, it was listed for 12 years on the Sentry Risk Table as the asteroid with the greatest known probability (5%) of impacting Earth. 2010 RF12 was recovered in August 2022, and now has a 12 year observation arc and a much better known orbit. As of the December 2022 solution which accounts for nongravitational forces, there is a 1-in-10 chance of an Earth impact on 5 September 2095.
(367789) 2011 AG5, provisional designation 2011 AG5, is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It has a diameter of about 140 meters (460 ft). It was removed from the Sentry Risk Table on 21 December 2012 and as such it now has a rating of 0 on the Torino Scale. It was recovered in December 2022 extending the observation arc from 4.8 years to 14 years. As of 2023, the distance between the orbits of Earth and 2011 AG5 is 0.0004 AU (60,000 km; 0.16 LD)
2006 JY26 is a near-Earth object that is also horseshoe companion to the Earth like 3753 Cruithne.
2011 XC2 (also written 2011 XC2) is a near-Earth asteroid roughly 60–140 meters (200–460 ft) in diameter that passed less than 1 lunar distance from Earth on 3 December 2011.
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.
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.
2014 MV67 (also written 2014 MV67) was a lost asteroid with an observation arc less than 1 day. It had an assumed orbital eccentricity and a very poorly constrained orbit. Depending on the orbit, it could have been a potentially hazardous asteroid, roughly 540 meters (1,770 feet) in diameter, or it could turn out to be a Mars-crosser or even a main-belt asteroid as were the cases with 2004 BX159 and 2010 GZ60. It was recovered by Pan-STARRS in September 2021 and is now known to be a Mars-crossing asteroid.
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.
2007 FT3 (also written 2007 FT3) is a lost asteroid with a short observation arc of 1.2 days that can not be recovered with targeted observations and awaits serendipitous survey observations. It has a poorly constrained orbit and has not been seen since 2007. It was first observed on 20 March 2007 when the asteroid was estimated to be 0.19 ± 0.01 AU (28.4 ± 1.5 million km) from Earth and had a solar elongation of 107 degrees. 2007 FT3 is the fourth largest asteroid with better than a 1-in-2 million cumulative chance of impacting Earth after (29075) 1950 DA, 1979 XB, and 101955 Bennu. With a cumulative Palermo Technical Impact Hazard Scale of -2.93, the poorly known orbit and assumed size place 2007 FT3 fifth on an unconstrained listing of the Sentry Risk Table. The asteroid is not expected to be near the Earth in October 2024.
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.
2005 ED224 was the soonest virtual impactor of an asteroid larger than 50 meters in diameter with a better than 1:1-million chance of impacting Earth. On 11 March 2023 the line of variations (LOV) showed a 1-in-500,000 chance of impact. It is estimated to be 54-meters in diameter and has a short observation arc of 3-days. On 11 March 2023 it was nominally expected to be 2.7 AU (400 million km) from Earth but had an uncertainty region billions of kilometers long. Since it has not been observed since 2005 and has an orbital period of 2.6±0.3 years, we do not know where on its orbit 2005 ED224 is. Between 2005 and 2023 it could have orbited the Sun 6.2 to 7.8 times. On 11 March 2030 it has a 1-in-6,300,000 chance of impact but is expected to be 3.5 AU (520 million km) from Earth (near the asteroid's farthest distance from the Sun). On 10 March 2064 it has a 1-in-2,600,000 chance of impact but is expected to be 3.2 AU (480 million km) from Earth.
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 EU is a small near-Earth object that should pass within 0.4 AU (60 million km) of Earth in 2024. On 27 February 2024 it has a 1-in-32,000 chance of impacting Earth. It is estimated to be 28-meters in diameter which would make it larger than the Chelyabinsk meteor. It has a short observation arc of 15 days and has not been observed since 17 March 2021 when it was 0.23 AU (34 million km) from Earth. On 27 February 2024 it is nominally expected to be 0.09 AU (13 million km) from Earth but has an uncertainty region of ±45 million km (0.30 AU). The nominal 2024 Earth approach would have the asteroid only brightening to apparent magnitude 23 near closest approach.
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.
References
- 1 2 3 4 5 "1979 XB". Minor Planet Center. Retrieved 31 August 2019.
- 1 2 "NEODyS-2 Risk List". NEODyS (Near Earth Objects – Dynamic Site). Archived from the original on 20 November 2018. Retrieved 8 March 2021.
- 1 2 3 4 5 "JPL Small-Body Database Browser: (1979 XB)" (1979-12-15 last obs.). Jet Propulsion Laboratory . Retrieved 31 August 2019. (Wayback Machine 2018-01-30)
- 1 2 3 4 5 "Earth Impact Risk Summary: 1979 XB". NASA/JPL Near-Earth Object Program Office. Archived from the original on 19 August 2019. Retrieved 30 August 2019. (Wayback Machine 2002)
- ↑ "Sentry: Earth Impact Monitoring". NASA/JPL Center for NEO Studies. Retrieved 7 August 2021. (Use Unconstrained Settings to reveal 1979 XB with impact probability below 1e-7)
- ↑ "1979XB Orbital Information". NEODyS (Near Earth Objects – Dynamic Site). Archived from the original on 31 August 2019. Retrieved 31 August 2019.
- 1 2 "1979XB Close Approaches". NEODyS (Near Earth Objects – Dynamic Site). Archived from the original on 30 August 2019. Retrieved 30 August 2019.
- 1 2 Go to JPL Horizons. Table Settings: only need "20. Observer range & range-rate" AND "39. Range & range-rate 3-sigmas".
RNG_3sigma = uncertainty range in km. (Soln.date: 2017-Apr-06 generates RNG_3sigma = 1.211291E9 for 2024-Dec-08) - 1 2 3 "1979XB Ephemerides for 2056". NEODyS (Near Earth Objects – Dynamic Site). Archived from the original on 4 April 2021. Retrieved 4 April 2019.
- 1 2 3 "Horizons Batch for 2056-12-12 Virtual Impactor". JPL Horizons . Retrieved 20 April 2021. RNG_3sigma = uncertainty range in km. (JPL#13/Soln.date: 2021-Apr-14 generates RNG_3sigma = 1.3E10 for 2056-Dec-12.)
- ↑ "1979XB Ephemerides for 2113-12-14". NEODyS (Near Earth Objects – Dynamic Site). Archived from the original on 31 August 2019. Retrieved 31 August 2019.
