Chelyabinsk meteorite

Chelyabinsk
Fragments of the meteorite that were first discovered at Lake Chebarkul.
Type	Ordinary chondrite LL5
Shock stage	S4
Weathering grade	W0 (pristine)
Country	Russia
Region	Chelyabinsk Oblast
Coordinates	54.955146°N 60.326614°E / 54.955146; 60.326614
Observed fall	Yes
Fall date	15 February 2013, 09:20 YEKT (UTC+06:00)
Found date	17 February 2013
TKW	TBD (53 fragments smaller than 1 cm at the moment).
Strewn field	Yes
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The Chelyabinsk meteorite is the fragmented remains of the large Chelyabinsk meteor of 15 February 2013 which reached the ground after the meteor's passage through the atmosphere. The descent of the meteor, visible as a brilliant superbolide in the morning sky, caused a series of shock waves that shattered windows, damaged approximately 7,200 buildings and left 1,500 people injured. The resulting fragments were scattered over a wide area.

Naming

The meteor and meteorite are named after Chelyabinsk Oblast, over which the meteor exploded. An initial proposal was to name the meteorite after Lake Chebarkul, where one of its major fragments allegedly impacted and made a 6-metre-wide hole in the ice of the lake. The large meteorite has yet to be found, but smaller fragments were retrieved from the ice around the hole.

Composition and classification

The meteorite has been preliminarily classified as an ordinary chondrite. First estimates of its composition indicate about 10% of meteoric iron, as well as olivine and sulfites.

Asteroid

The impacting asteroid started to brighten up in the general direction of the Pegasus constellation, close to the East horizon where the Sun was starting to rise. The impactor belonged to the Apollo group of near-Earth asteroids.

The asteroid had an approximate size of 18 metres (59 ft) and a mass of about 9,100 tonnes (10,000 short tons) before it entered the denser parts of Earth's atmosphere and started to ablate. At an altitude of about 23.3 km (14.5 miles) the body exploded in an air burst. Meteorite fragments of the body landed on the ground.

Meteorite

Scientists collected 53 samples nearby a 6-metre-wide hole in the ice of Lake Chebarkul, thought to be the result of a single meteorite fragment impact. The specimens are all under 1 centimetre in size and initial laboratory analysis confirmed their meteoric origin.

In June 2013, Russian scientists reported that further investigation by magnetic imaging below the location of the ice hole in Lake Chebarkul has identified a 60 centimetres (2.0 ft)-size large meteorite buried in the mud at the bottom of the lake. The chunk is estimated to weigh roughly 300 kilograms (660 lb), but has not yet been recovered.

In the aftermath of the superbolide air burst, a large number of small meteorite fragments fell on areas west of Chelyabinsk, including Deputatskoye, generally at terminal velocity, about the speed of a piece of gravel dropped from a skyscraper. Local residents and schoolchildren located and picked up some of the meteorites, many located in snowdrifts, by following a visible hole that had been left in the outer surface of the snow. Speculators have been active in the informal market for meteorite fragments that has rapidly emerged.

As of 18 February 2013, some reports surfaced of people trying to sell fake meteorites on the Internet.

Gallery

• 
  Size comparison of the meteor size to some other objects
• 
  The meteor's path relative to ground.
• 
  Researcher holds the sample after finding it at Chebarkul lake
• 
  Ural Federal University scientist Victor Grohovsky talks to press during presentation of analysis results in Ekaterinburg

External links

• Scientists study 53 tiny meteorites from Russian fireball (Astro Bob : 18 February 2013)
• Digging for "Chebarkul" meteorites in the snow, new pix plus an orbit (Astro Bob : 23 February 2013)