Sikhote-Alin meteorite
Sikhote-Alin | ||
---|---|---|
Observed fall Yes | | |
Fall date | February 12, 1947 | |
TKW | >23 tonnes (25 short tons)[1] | |
Strewn field | Yes | |
Related media on Wikimedia Commons |
An
Impact
At around 10:30 AM on 12 February 1947, eyewitnesses in the
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
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
Composition and classification
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]
- individual, fusion crust and signs of atmospheric ablation
- 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
-
Thumbprinted individual
-
Oriented individual
-
Shrapnel sample
-
A piece on display at Meteor Crater, Arizona
See also
- Glossary of meteoritics
- Meteorite
- Meteorite fall
- Chelyabinsk Meteor
- List of meteor air bursts
References
- ^ a b c Meteoritical Bulletin Database: Sikhote-Alin. Archived from the original on 2012-01-30.
- ISBN 0878423028.
- ^ "Sikhote-Alin Meteorite". meteoritemarket.com. Retrieved 4 June 2021.
- ^ Burns, Philip R. "Pib". "Meteorite Stamps and Coins". Archived from the original on 2000-01-21.
- ^ "Sikhote Alin". Dow Planetarium. Archived from the original on 2006-05-21.
- ^ "Witnesses and orbit". meteorite-rencon.com. Retrieved 4 June 2021.
- ISBN 9781848001572.
- ^ Bibcode:1996Met.....2....8G. Archived from the originalon 2010-06-12.
- ^ "Sikhote-Alin". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved 2009-08-19.[dead link]
- ^ Buchwald, Vagn F. (1975). Handbook of Iron Meteorites – Their History, Distribution, Composition and Structure. Vol. 3. University of California Press. pp. 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.
External links
- "Exposition 'Meteorites'". Fersman Mineralogical Museum. Moscow, Russia: Russian Academy of Sciences. Archived from the original on 1999-04-20.