Digging for “Chebarkul” meteorites in the snow, new pix plus an orbit

“Chebarkul” meteorite fragment with black fusion crust, pale crystalline interior and black, glassy shock veins caused by the impact that liberated the meteorite from its home asteroid millions of years ago. Click to enlarge. Credit: Laboratory of Meteoritics, Vernadsky Institute

We’ve seen the first fragments of meteorites from last Friday’s Russian fireball. I thought you’d also like a look at more recent, high-quality close-ups of larger pieces.  All these images are from the Laboratory of Meteoritics at the Vernadsky Institute in Moscow. Scientists at the Institute are calling the new meteorites “Chebarkul”, after the town where the first fragments were collected from the lake of the same name. A formal name has yet to be announced.

1.2-inch (30 mm) slice of the meteorite showing nice shock veins, a few rounded grains called chondrules and already a bit of rusting due to the inevitable contamination by oxygen and water vapor. Click to enlarge. Credit: Laboratory of Meteoritics, Vernadsky Institute

The Russian meteorite resembles Park Forest, a meteor that came blazing out of the sky over the Chicago suburb Park Forest shortly before midnight March 26, 2003 and dropped numerous stones totaling about 40 lbs. (18 kilograms). One struck a fire station and another crashed through the roof of Noe Garza’s home and into a bedroom where a young boy was sleeping. Luckily, no one was hurt.

A 1.4-inch slice of the Park Forest meteorite that fell in 2003 shows similar shock veins and a shattered texture similar to the top image fo Chebarkul. Photo: Bob King

Chebarkul’s preliminary classification is L5 or LL5 chondrite; in plain English, that’s a stony meteorite with a low iron content heated to the point where much of its original mineral structure has re-crystallized. Gouged from the crust of a distant asteroid long ago, the huge boulder was pitched by the planet Jupiter into an Earth-crossing orbit and ultimately met its fate on Feb.15, 2013.  Park Forest is classified as an L5 and has a similar history.

The Institute further adds:
“According to Cyril Lorenz, meteorite scientist of the Laboratory of Meteoritics, further study of the samples revealed that meteor shower samples have different compositions  — chondrite, breccia (ie. broken rock) and impact melt. Thus (the) meteorite is a shock melted breccia.”

Animation of the orbit Chelybinsk meteoroid via Ferrin and Zuluaga. Meteoroid is the name given a meteor while still orbiting the sun before it enters Earth’s atmosphere.

Astrophysicists Jorge Zuluaga and Ignacio Ferrin just released a paper describing a preliminary orbit for the Chebarkul / Chelyabinsk meteoroid. They used video taken by a camera at the Revolution Square in the city of Chelyabinsk as well as other videos made by eyewitnesses in the nearby town of Korkino to calculate the trajectory of the body in the atmosphere.

Chebarkul appears to be an Apollo asteroid with an orbit that routinely crossed Earth’s. The Park Forest meteorite was also an Apollo family member. Illustration: Bob King

Although some uncertainties remain, the object is (was) a member of the Apollo family of asteroids, named for 1862 Apollo, discovered in 1932. Apollos cross Earth’s orbit on a routine basis when they’re nearest the sun. Chebarkul’s most recent crossing was of course its last.

Sasha Zarezina, 8, who lives in a small Siberian village, looks for and finds meteorites in the snow on Feb. 19, 2013. Video by Ben Solomon, New York TImes

Frame grab from BBC vidoe of local meteorite Boris Vasiliev describing his meteorite find on Chebarkul Lake. Click to see full video. Credit: BBC

More and more pieces of this erstwhile Apollo are turning up all the time. You’ll enjoy the video of Sasha hopping around in the snow digging for meteorite gold. Makes me wish I could be there not only looking for space rocks with the kids but covering the story with my camera.

Expedition of the Meteorite Committee of Russian Academy of Sciences (KMET RAN) collected the first samples of the “Chebarkul” meteorite. Click to enlarge. Credit: Laboratory of Meteoritics, Vernadsky Institute

2 Responses

  1. A much more detailled analysis of the fireball, its trajectory and fragmentation sequence has appeared today in the IAU Central Bureau for Astronomical Telegrams’ Central Bureau Electronic Telegram #3423, unfortunately behind a paywall. Interestingly the authors – meteor celebrities Jiri Borovicka, Pavel Spurny and Lukas Shrbeny from Ondrejov Observatory in the Czech Republic – dare to make detailled predictions about where what should have come down: “The mass of the largest fragment, which landed in the lake Chebarkul, was estimated to be 200-500 kg. One or two meteorites of the mass of several tens of kg can be expected not far from the village Travniki. One piece of mass approximately 1 kg may have landed to the northwest of Shchapino. Numerous small fragments can be expected in the wide band located about 5 km south of the trajectory” – what are we waiting for? Let’s go! :-)

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