Astronomy:2008 TC3

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2008 TC3
Estimated path and altitude of the meteor in red, with the possible location for the METEOSAT IR fireball (bolide) as orange crosshairs and the infrasound detection of the explosion in green.
Discovery
Discovered byCatalina Sky Survey
Discovery dateOctober 6, 2008, 06:39 UTC
Designations
2008 TC3
Minor planet category
Orbital characteristics[1]
Epoch October 7, 2008 (JD 2454746.5)
Uncertainty parameter 4
Observation arc1 day (575 observations)
|{{{apsis}}}|helion}}1.71644 astronomical unit|AU (256.776 Gm)
|{{{apsis}}}|helion}}0.899957 AU (134.6317 Gm)
1.308201 AU (195.7041 Gm)
Eccentricity0.312065
Orbital period1.50 yr (546.53 d)
Mean anomaly330.7541°
Mean motion0.6587071°/day
Inclination2.54220°
Longitude of ascending node194.101138°
|{{{apsis}}}|helion}}2008-Nov-20
234.44897°
Jupiter MOID3.57975 AU (535.523 Gm)
Physical characteristics
Dimensions4.1 metres (13.5 ft)
Mass80,000 kilograms (180,000 lb)
Mean density~1.5 g/cm3
Rotation period0.0269409 h (1.61645 min)[1]
Geometric albedo0.1±0.03
F/M
Absolute magnitude (H)30.4[1]


2008 TC3 (Catalina Sky Survey temporary designation 8TA9D69) was an 80-tonne (80-long-ton; 90-short-ton), 4.1-meter (13 ft) diameter asteroid[2] that entered Earth's atmosphere on October 7, 2008.[3] It exploded at an estimated 37 kilometers (23 mi) above the Nubian Desert in Sudan. Some 600 meteorites, weighing a total of 10.5 kilograms (23.1 lb), were recovered; [4] many of these belonged to a rare type known as ureilites, which contain, among other minerals, nanodiamonds.[2][5][6]

It was the first time that an asteroid impact had been predicted before its entry into the atmosphere as a meteor.[7]

Discovery

An animation of 2008 TC3's excited rotation prior to entering the atmosphere

The asteroid was discovered by Richard A. Kowalski at the Catalina Sky Survey (CSS) 1.5-meter telescope at Mount Lemmon, north of Tucson, Arizona, US, on October 6, 06:39:51 UTC, 20 hours before the impact.[8][9][10]

It was notable as the first such body to be observed and tracked prior to reaching Earth.[7] The process of detecting and tracking a near-Earth object, an effort sometimes referred to as Spaceguard, was put to the test. In total, 586 astrometric and almost as many photometric observations were performed by 27 amateur and professional observers in less than 19 hours and reported to the Minor Planet Center, which in eleven hours issued 25 Minor Planet Electronic Circulars with new orbit solutions as observations poured in. On October 7, 01:49 UTC,[10] the asteroid entered the shadow of the Earth, which made further observations impossible.

The photometric observations provided information on the shape and spin of the asteroid. Spectral observations that were performed by astronomers at the 4.2 metres (170 in) William Herschel Telescope at La Palma, Canary Islands are consistent with an F-type, C-type or M-type asteroid.

Impact predictions were performed by University of Pisa's CLOMON 2 semi-automatic monitoring system[11][12] as well as Jet Propulsion Laboratory's Sentry system. The trajectory showed intersection with Earth's surface at roughly [ ⚑ ] 20°18′N 33°30′E / 20.3°N 33.5°E / 20.3; 33.5 (2008 TC3 projected impact)[13] though the object was expected to break up perhaps 100–200 kilometers (60–120 mi) west as it descended, somewhat east of the Nile River, and about 100 kilometers (60 mi) south of the Egypt–Sudan border.

Entry

Meteosat 8/EUMETSAT infrared image of the explosion
Animation of 2008 TC3's orbit
  2008 TC3 ·   Sun ·   Earth

The meteor entered Earth's atmosphere above northern Sudan at 02:46 UTC (05:46 local time) on October 7, 2008, with a velocity of 12.8 kilometers per second (8.0 mi/s) at an azimuth of 281 degrees and an altitude angle of 19 degrees to the local horizon. It exploded ~37 kilometers above the ground with the energy of 0.9 to 2.1 kilotons of TNT over a remote area of the Nubian Desert, causing a large fireball or bolide.[14]

The Times reported that the meteor's "light was so intense that it lit up the sky like a full moon", and pilots of an airliner 1,400 km (870 mi) away over the Republic of Chad, who had been warned about the imminent impact, reported seeing three bright flashes in short succession.[15] A webcam captured the flash lighting up El-Gouna beach 725 kilometres (450 mi) north of the explosion (see this webcam frame).[16] A low-resolution image of the explosion was captured by the weather satellite Meteosat 8.[17] The Meteosat images place the fireball at [ ⚑ ] 21°00′N 32°09′E / 21.00°N 32.15°E / 21.00; 32.15 (2008 TC3 fireball).[18]

According to U.S. government sources[19][20] U.S. satellites detected the impact at 02:45:40 UT, with the initial detection at [ ⚑ ] 20°54′N 31°24′E / 20.9°N 31.4°E / 20.9; 31.4 (2008 TC3 initial detection) at 65.4 kilometers (40.6 mi; 35.3 nmi) altitude and final explosion at [ ⚑ ] 20°48′N 32°12′E / 20.8°N 32.2°E / 20.8; 32.2 (2008 TC3 final explosion) at 37 kilometers (23 mi; 20 nmi) altitude. These images have not been publicly released. The calculated total impact energy was 1 kilotons of TNT.

Infrasound detector arrays in Kenya also detected a sound wave from the direction of the expected impact corresponding to energy of 1.1 to 2.1 kilotons of TNT.[21] Asteroids of this size hit Earth about two or three times a year.[22]

Recovered fragments

Jenniskens in the Nubian Desert, February 2009

A search of the impact zone that began on December 6, 2008, turned up 15 meteorites in three days. These meteorites are collectively named Almahata Sitta[23] (Arabic: المحطة ستة), which means "Station Six"[24] on the railroad between Wadi Halfa and Khartoum, Sudan. This search was led by Peter Jenniskens from the SETI Institute, California and Muawia Shaddad of the University of Khartoum in Sudan and carried out with the collaboration of 45 students and staff of the University of Khartoum. Numerous witnesses were interviewed, and the hunt was guided with a search grid and specific target area produced by NASA's Jet Propulsion Laboratory in Pasadena, California.[25][26][27][28][29] Follow up searches in 2008 and 2009 involved over a hundred students and collected 10.5 kilograms (23 lb) of rock in some 600 fragments. [4]

From the initial finds, one sample of the Almahata Sitta meteorite was sent for analysis to a consortium of researchers led by Jenniskens, the Almahata Sitta consortium, including NASA Ames in California, the Johnson Space Center in Houston, the Carnegie Institution of Washington, and Fordham University in New York City. This first sample measured was an anomalous ultra-fine-grained porous polymict ureilite achondrite, with large carbonaceous grains. Almahata Sitta is the first observed polymict ureilite fall. Much new information was obtained on the nature of the ureilite parent body. The astronomical observations, combined with spectral reflectance measurements of the meteorite, identified 2008 TC3 as an F-type asteroid. For the first time, asteroid class and meteorite type were linked.[2] [30]

Already during the first recovery, it was noticed that meteorites of several different appearances were present in the strewnfield.[2] Later work revealed over 20 different meteorite types, most of which were various types of ureilites, but others were enstatite chondrites, ordinary chondrites, carbonaceous chondrites, and some rare and unique meteorite types. Studies in the Almahata Sitta Consortium showed that all types fell from 2008 TC3, the first time a single meteorite fall proved a mixed bag of meteorite types. The discovery of some fragile carbonaceous chondrites and the prominent deposition of dust in the atmosphere during entry suggested the possibility that what was found on the ground may not reflect what came in, from which alternative identities were proposed (e.g., [1]).

In other work, the nanodiamonds found in the meteorite were shown to have grown slowly, suggesting that the source was an earlier planet-sized object in the Solar System.[31] Those claims have since been challenged.

More recently, in December 2020, further studies on the fragments have been reported. These studies revealed an extremely rare form of hydrated crystals, in a fragment called AhS 202, known as amphibole, suggesting to the researchers that 2008 TC3 early on likely belonged to a very large Ceres-class dwarf planet.[32]

Richard Kowalski, who discovered the object, received a tiny fragment of Almahatta Sitta, a gift from friends and well-wishers on the Minor Planet Mailing List, which Kowalski founded in order to help connect professional and amateur astronomers.[33]

  • Meteosat 8/EUMETSAT visual image of first light flare from 2008 TC3 with lat/long reference
    Meteosat 8/EUMETSAT visual image of first light flare from 2008 TC3 with lat/long reference
  • Meteosat 8/EUMETSAT IR image of main fireball from 2008 TC3
    Meteosat 8/EUMETSAT IR image of main fireball from 2008 TC3
  • Meteosat images combined, showing offset from first light flare to main IR flare
    Meteosat images combined, showing offset from first light flare to main IR flare

See also

References

  1. ↑ 1.0 1.1 1.2 "JPL Small-Body Database Browser: (2008 TC3)". Jet Propulsion Laboratory. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2008TC3;cad=1. 
  2. ↑ 2.0 2.1 2.2 2.3 Jenniskens, P. (2009). "The impact and recovery of asteroid 2008 TC3". Nature 458 (7237): 485–488. doi:10.1038/nature07920. PMID 19325630. Bibcode: 2009Natur.458..485J. 
  3. ↑ Plait, P. (October 6, 2008). "Incoming!!!". Bad Astronomy. http://blogs.discovermagazine.com/badastronomy/2008/10/06/incoming-2/. 
  4. ↑ 4.0 4.1 Shaddad, M. H. (2010). "The recovery of asteroid 2008 TC3". Meteoritics and Planetary Science 45: 1557–1589. doi:10.1111/j.1945-5100.2010.01116.x. https://onlinelibrary.wiley.com/doi/10.1111/j.1945-5100.2010.01116.x. 
  5. ↑ Chang, K. (March 25, 2009). "Recovered Pieces of Asteroid Hold Clues to Early History". The New York Times. https://www.nytimes.com/2009/03/26/science/space/26asteroid.html?ref=us. 
  6. ↑ Borenstein, S. (March 26, 2009). "Astronomers catch a shooting star for 1st time". ABC news. The Associated Press. https://abcnews.go.com/Technology/Space/WireStory?id=7175837&page=2. 
  7. ↑ 7.0 7.1 Roylance, F. (October 7, 2008). "Predicted meteor may have been sighted". Maryland Weather. http://weblogs.marylandweather.com/2008/10/predicted_meteor_may_have_been.html. 
  8. ↑ Williams, G. V. (October 6, 2008). "MPEC 2008-T50". Minor Planet Center. http://www.cfa.harvard.edu/mpec/K08/K08T50.html. 
  9. ↑ Huntington, J. (October 7, 2008). "Small Asteroid Enters Earth's Atmosphere". eFluxMedia. http://www.efluxmedia.com/news_Small_Asteroid_Enters_Earths_Atmosphere_26024.html. 
  10. ↑ 10.0 10.1 Chesley, S.; Chodas, P.; Yeomans, D. (November 4, 2008). "Asteroid 2008 TC3 Strikes Earth: Predictions and Observations Agree". Near Earth Object Program. NASA. http://neo.jpl.nasa.gov/news/2008tc3.html. 
  11. ↑ "NEODys Main Risk Page". https://newton.spacedys.com/neodys/. 
  12. ↑ "NEODys 2008 TC3 page". https://newton.spacedys.com/neodys/index.php?pc=1.1.0&n=2008TC3. 
  13. ↑ Mike (October 6, 2008). "Very near NEO Meteoroid impact!". MKVH.de. http://mkvh.de/ast/serendipity/index.php?/archives/9-Very-near-NEO-Meteoroid-impact-!.html. 
  14. ↑ "Astronomers predict shooting star over Sudan from space boulder". Agence France-Presse. October 6, 2008. http://afp.google.com/article/ALeqM5jOHHF4wcyteiUj5AlJP69dIMb0yA. 
  15. ↑ Simon, P. (October 8, 2008). "Weather Eye: NASA spots asteroid before annihilation". The Times. http://www.timesonline.co.uk/tol/news/weather/article4902427.ece. 
  16. ↑ Javaux, G.. "2008 TC3... Première détection d'un astéroïde avant son impact sur Terre... quelques heures plus tard" (in fr). http://pagesperso-orange.fr/pgj/2008_TC3.htm. "Une webcam de surveillance, située sur la plage de la Mer Rouge à El Gouna en Egypte, a enregistré indirectement le flash de l'explosion qui s'est produit à environ 725 km plus au sud." 
  17. ↑ "Asteroid Impact". SpaceWeather.com. October 8, 2008. http://www.spaceweather.com/archive.php?view=1&day=08&month=10&year=2008. 
  18. ↑ "m8 HRV 200810070245". October 8, 2008. http://www.eumetsat.int/groups/ops/documents/image/img_asteroid_impact_hrv.jpg. 
  19. ↑ "Asteroid Update". SpaceWeather.com. October 15, 2008. http://www.spaceweather.com/archive.php?month=10&day=15&year=2008&view=view. 
  20. ↑ "Fireball detection". University of Western Ontario. October 15, 2008. http://meteor.uwo.ca/~pbrown/usaf/usg282.txt. 
  21. ↑ "Impact of Asteroid 2008 TC3 Confirmed". Near Earth Object Program. October 7, 2008. http://neo.jpl.nasa.gov/news/news160.html. 
  22. ↑ Borenstein, S. (October 6, 2008). "Small Asteroid Headed for Light Show Over Africa". ABC News. The Associated Press. https://abcnews.go.com/Technology/wireStory?id=5968166. 
  23. ↑ "Almahata Sitta". Meteoritical Bulletin Database. August 12, 2013. http://www.lpi.usra.edu/meteor/metbull.php?code=48915. 
  24. ↑ Gebauer, S. (April 16, 2008). "Station Nr. 6. – Nubian Desert". Panoramio. https://www.panoramio.com/photo/9417877. 
  25. ↑ "NASA Team Finds Riches in Meteorite Treasure Hunt". NASA. March 27, 2009. http://www.nasa.gov/topics/solarsystem/features/asteroid_treasure_hunt.html. 
  26. ↑ "Found: Pieces of meteorite spotted before impact". New Scientist (2697): 15. February 25, 2009. https://www.newscientist.com/article/mg20126974.800-found-pieces-of-meteorite-spotted-before-impact.html. 
  27. ↑ Shiga, D. (February 19, 2009). "First tracked space rock recovered after impact". New Scientist. https://www.newscientist.com/article/dn16635-first-tracked-space-rock-recovered-after-impact.html. 
  28. ↑ Courtland, R. (March 25, 2009). "Meteorite hunters 'strike gold' in Sudan". New Scientist. https://www.newscientist.com/article/dn16843-meteorite-hunters-strike-gold-in-sudan.html. Retrieved April 4, 2009. 
  29. ↑ Kwok, R. (March 26, 2009). "Astronomy: The Rock That Fell to Earth". Nature 458 (7237): 401–403. doi:10.1038/458401a. PMID 19325604. 
  30. ↑ "Life's Building Blocks Found on Surprising Meteorite". Space.com. December 16, 2010. http://www.space.com/scienceastronomy/asteroid-collision-meteoroid-amino-acids-life-101215.html. 
  31. ↑ Nabiei, Farhang et al. (April 17, 2018). "A large planetary body inferred from diamond inclusions in a ureilite meteorite". Nature Communications (Springer Nature) 9 (1): 1327. doi:10.1038/s41467-018-03808-6. ISSN 2041-1723. PMID 29666368. Bibcode: 2018NatCo...9.1327N. 
  32. ↑ Dockrill, Peter (22 December 2020). "Meteorite Clues Point to a Huge, Unknown Object in The Early Solar System". SpaceAlert.com. https://www.sciencealert.com/a-huge-unknown-object-once-roamed-our-ancient-solar-system-scientists-say. 
  33. ↑ Lakdawalla, E. (September 20, 2009). "A piece of an asteroid returns to the telescope that discovered it". The Planetary Society. http://www.planetary.org/blog/article/00002104/. 

Further reading

Map all coordinates using: OpenStreetMap 
Download coordinates as: KML · GPX
External images
An image of 2008 TC3
Animation of 2008 TC3
Smoky trail (spaceweather.com November 8, 2008)



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