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An iron meteorite fell on the Sikhote-Alin Mountains, in southeastern Russia, in 1947. Large iron meteorite falls have been witnessed and fragments recovered but never before, in recorded history, a fall of this magnitude.[2] An estimated 23 tonnes[1] of fragments survived the fiery passage through the atmosphere and reached the Earth.

Sikhote-Alin
Thumbprinted Sikhote-Alin sample
TypeIron
Structural classificationOctahedrite, coarsest
GroupIIAB
Composition93% Fe, 5.9% Ni, 0.42% Co, 0.46% P, 0.28% S
CountryRussia
RegionSikhote-Alin Mountains, Primorsky Krai, Far Eastern Federal District
Coordinates46°09′36″N 134°39′12″E[1]
Observed fallYes
Fall dateFebruary 12, 1947
TKW>23 tonnes (25 short tons)[1]
Strewn fieldYes
Related media on Wikimedia Commons

Impact


The 10th anniversary stamp. It reproduces a painting by P. J. Medvedev.
The 10th anniversary stamp. It reproduces a painting by P. J. Medvedev.

At around 10:30 AM on 12 February 1947, eyewitnesses in the Sikhote-Alin Mountains, Primorye, Soviet Union, observed a large bolide brighter than the sun that came out of the north and descended at an angle of about 41 degrees. The bright flash and the deafening sound of the fall were observed for 300 kilometres (190 mi) around the point of impact not far from Luchegorsk and approximately 440 km (270 mi) northeast of Vladivostok. A smoke trail, estimated at 32 km (20 mi) long, remained in the sky for several hours.

As the meteor, traveling at a speed of about 14 km/s (8.7 mi/s), entered the atmosphere, it began to break apart, and the fragments fell together, some burying themselves 6 metres (20 ft) deep.[3] At an altitude of about 5.6 km (3.5 mi), the largest mass apparently broke up in a violent explosion called an air burst.

On November 20, 1957[4] the Soviet Union issued a stamp for the 10th anniversary of the Sikhote-Alin meteorite shower. It reproduces a painting by P. I. Medvedev, a Soviet artist who witnessed the fall: he was sitting in his window starting a sketch when the fireball appeared, so he immediately began drawing what he saw.[5]


Orbit


Because the meteor fell during daytime, it was observed by many eyewitnesses. Evaluation of this observational data allowed V. G. Fesenkov, then chairman of the meteorite committee of the USSR Academy of Science, to estimate the meteoroid's orbit before it encountered the Earth. This orbit was ellipse-shaped, with its point of greatest distance from the sun situated within the asteroid belt, similar to many other small bodies crossing the orbit of the Earth.[6] Such an orbit was probably created by collisions within the asteroid belt.


Size


Sikhote-Alin is a massive fall with the pre-atmospheric mass of the meteoroid estimated at approximately 90,000 kg (200,000 lb).[7] A more recent estimate by Tsvetkov (and others) puts the mass at around 100,000 kg (220,000 lb).[8]

Krinov estimated the post-atmospheric mass of the meteoroid at some 23,000 kg (51,000 lb).


Strewn field and craters


The strewn field for this meteorite covered an elliptical area of about 1.3 km2 (0.50 sq mi). Some of the fragments made impact craters, the largest of which was about 26 m (85 ft) across and 6 m (20 ft) deep.[9] Fragments of the meteorite were also driven into the surrounding trees, embedding themselves.


Composition and classification


Section
Section

The Sikhote-Alin meteorite is classified as an iron meteorite belonging to the meteorite group IIAB and with a coarse octahedrite structure. It is composed of approximately 93% iron, 5.9% nickel, 0.42% cobalt, 0.46% phosphorus, and 0.28% sulfur, with trace amounts of germanium and iridium. Minerals present include taenite, plessite, troilite, chromite, kamacite, and schreibersite.[10]


Specimens


Specimens of the Sikhote-Alin Meteorite are basically of two types:[8]

  1. individual, thumbprinted or regmaglypted specimens, showing fusion crust and signs of atmospheric ablation
  2. shrapnel or fragmented specimens, sharp-edged pieces of torn metal showing evidence of violent fragmentation

The first type probably broke off the main object early in the descent. These pieces are characterized by regmaglypts (cavities resembling thumb prints) in the surface of each specimen. The second type are fragments which were either torn apart during the atmospheric explosions or blasted apart upon impact on the frozen ground. Most were probably the result of the explosion at 5.6 km (3.5 mi) altitude.

A large specimen is on display in Moscow. Many other specimens are held by Russian Academy of Science and many smaller specimens exist in the collectors' market.


See also



References


  1. Meteoritical Bulletin Database: Sikhote-Alin. Archived from the original on 2012-01-30.
  2. Norton, O. Richard (1998). Rocks From Space. Missoula, Montana: Mountain Press. p. 103. ISBN 0878423028.
  3. "Sikhote-Alin Meteorite". meteoritemarket.com. Retrieved 4 June 2021.
  4. Burns, Philip R. "Pib". "Meteorite Stamps and Coins". Archived from the original on 2000-01-21.
  5. "Sikhote Alin". Planetarium de Montreal. Archived from the original on 2006-05-21.
  6. "Witnesses and orbit". meteorite-rencon.com. Retrieved 4 June 2021.
  7. Norton, O. Richard; Chitwood, Lawrence A. (2008). Field Guide to Meteors and Meteorites. London: Springer-Verlag. p. 47. ISBN 9781848001572.
  8. Gallant, Roy (February 1996). "Sikhote-Alin Revisited". Meteorite Magazine. Arkansas Center for Space and Planetary Sciences, University of Arkansas. 2: 8. Bibcode:1996Met.....2....8G. Archived from the original on 2010-06-12.
  9. "Sikhote-Alin". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved 2009-08-19. [dead link]
  10. Buchwald, Vagn F. (1975). HANDBOOK OF IRON METEORITES Their History, Distribution, Composition and Structure. University of California Press. pp. Vol 3, Pages 1123–1130. Group lIB. 5.90% Ni, 0.42% Co, 0.46% P, 0.28% S, 52 ppm Ga, 161 ppm Ge , 0.03 ppm Jr.


Wikimedia Commons has media related to Sikhote-Alin meteorite.

На других языках

[de] Sikhote-Alin (Meteorit)

Sikhote-Alin (russ. Сихотэ-Алинский метеорит) war ein Eisenmeteorit, der am Morgen des 12. Februars 1947 mit einer Masse von 100–200 Tonnen und einem Durchmesser von 3–4 Metern[2][3] und mit einer Geschwindigkeit von 50.000 km/h in die Erdatmosphäre über Ostsibirien eintrat. Der am Taghimmel hell sichtbare Bolide flog südwärts über das Sichote-Alin-Gebirge (Сихотэ-Алинь, 500 Kilometer nördlich von Wladiwostok) hinweg, wobei er eine stundenlang beobachtbare Rauchspur von über 30 Kilometer Länge hinterließ. Unter vielen weithin hörbaren Donnerschlägen zerplatzte der Meteorit schließlich, wobei mehrere tausend Bruchstücke als Meteoritenschauer innerhalb eines elliptischen Streufelds von 4 km Breite und 12 km Länge niedergingen. Dabei entstanden über 120 Einschlagkrater; der größte war 6 Meter tief und hatte einen Durchmesser von 28 Meter.
- [en] Sikhote-Alin meteorite

[es] Meteorito de Sijoté-Alín

El meteorito de Sijoté-Alín (en ruso: Сихотэ-Алинский метеорит) o Sijoté-Alín (Сихотэ-Алинь)[1] es un meteorito metálico caído en Rusia en el año 1947 sobre las montañas Sijoté-Alín. Esta lluvia de meteoritos fue la más grande de la historia reciente. Se estima que 23 toneladas[2] de fragmentos sobrevivieron al ardiente paso por la atmósfera y llegaron a la Tierra.

[ru] Сихотэ-Алинский метеорит

Сихотэ́-Али́нский метеори́т (или Сихотэ-Алинский железный метеоритный дождь 1947 года) — железный метеорит, разрушившийся при входе в атмосферу и выпавший в виде метеоритного дождя. Общая масса осколков оценивается в 60—100 тонн. Официальными экспедициями Академии наук собрано более 3500 фрагментов общей массой 27 тонн. Масса собранных нелегальными «старателями» обломков также может превышать 30 тонн — на вершине и склонах сопки в районе кратеров практически невозможно найти даже небольшие фрагменты, а на рынке метеоритов сихотэ-алиньский материал представлен более чем широко. На месте падения сохранилась только та часть обломков, которые попали в болото и русла ручьев, что оценивается не более чем в половину общей массы. Крупнейший целый фрагмент имеет массу 1745 кг. Другие — 1000, 700, 500, 450, 350 кг и меньше.[1] Входит в десятку крупнейших метеоритов мира.


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