Sikhote-Alin (meteorite)
 
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Location of the Sikhote-Alin scattering ellipse in Russia
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Position of the scattered ellipse of Sikhote-Alin in the Primorye region
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Sikhote-Alin (Russian Сихотэ-Алинский метеорит) was an iron meteorite that fell on the morning of February 12, 1947 with a mass of 100-200 tons and a diameter of 3-4 meters and at a speed of 50,000 km / h in the Earth atmosphere entered over Eastern Siberia . The bolide , brightly visible in the daytime sky, sped south over the Sichote-Alin Mountains (Сихотэ-Алинь, 500 kilometers north of Vladivostok ), leaving behind a trail of smoke over 30 kilometers long that could be observed for hours . With many thunderclaps that could be heard from afar, the meteorite finally burst, with several thousand fragments falling as a meteor shower within an elliptical scattered field 4 km wide and 12 km long. Over 120 impact craters were created ; the largest was 6 meters deep and 28 meters in diameter.
So far, more than 8000 meteorite fragments with a total mass of 30 tons have been collected in the impassable area of the Primorye region near the Pacific; the largest single fragment weighed 1.75 tons. Many of the fragments were severely deformed when they hit the frozen ground and are known as "shrapnel".
Witness accounts and research history
The meteorite impact was described by more than 240 eyewitnesses. One of them was the Russian artist Pyotr Ivanovich Medvedev , who captured the event in an oil painting. The painting later served as a template for a special postage stamp issued by the Soviet Union on the occasion of the tenth anniversary of the meteorite impact .
The traces of the impact in the remote, snow-covered jungle region were first discovered from the air. 75 km east of Dalnerecensk, two pilots saw fallen trees and thrown earth, which was clearly visible against the snow. Geologists from Khabarovsk fought their way through the snow for three days, stumbled upon a 30-meter crater on February 24 and found the first pieces of iron in small depressions. Another expedition in April was led by Prof. EL Krinow , who had already investigated the Stony Tunguska impact of 1908 around 1925 . The group found 122 craters over 1 meter and sharp-edged and molten pieces of iron. Initially a scattered ellipse of 1 × 2 km was searched, but a few years later the meteor researcher Valentin Tsvetkow expanded it to 4 × 12 km in the south-southwest direction. The chemical analyzes showed that the meteoroid consisted of more than 90% iron and therefore probably came from the core of a larger asteroid .
Origin and analysis of the fragments
The original meteoroid comes from the asteroid belt , as an orbit determination from the witness reports showed. Its remains are classified as Group IIB coarse octahedrite .
The analysis of the meteorites found showed the average chemical composition of 93% iron , 5.9% nickel , 0.42% cobalt , 0.46% phosphorus , 0.28% sulfur , 161 ppm germanium , 52 ppm gallium and 0.03 ppm Iridium .
The fragments of the iron meteorite show an unusually diverse range of shapes - from small, sharp-edged shrapnel created by several explosions to larger, partially melted chunks to bizarre structures with hard points and large honeycomb depressions.
Numerous European museums have fragments of this meteor fall, a larger number z. B. the meteorite collections in the Vienna Natural History Museum and in Munich.
Unique item from the Sikhote-Alin meteor shower
Section through a Sikhote-Alin meteorite with Troilit inclusions and Neumann lines
See also
Web links
Individual evidence
- ^ Sikhote-Alin in the Earth Impact Database
- ↑ Spiegel Online: Meteorite impact 1947
- ↑ Sikhote-Alin Revisited , Meteorite Magazine Feb. 1996, University of Arkansas ( Memento of the original from June 12, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
Coordinates: 46 ° 9 ′ 35 ″ N , 134 ° 39 ′ 11 ″ E