Tracked asteroid debris collected

Debris from an asteroid tracked as it fell to Earth has been recovered by scientists for the first time, says a report in the science journal Nature.

Nearly 50 fragments of the asteroid were collected from the desert in Sudan where it fell last October.

Scientists say the discovery offers a unique opportunity to study the asteroid's route and chemical make-up.

It will also give new insights into how to tackle any larger asteroids heading towards Earth in the future.

The car-sized lump of rock, known as 2008 TC3, was detected by astronomers in the US state of Arizona in October last year.

It was tracked by telescopes around the world until it disintegrated in the atmosphere above the Nubian desert region of Sudan.

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Peter Jenniskens, author of the report and a scientist at the Seti Institute in California, then travelled to Sudan with a team of researchers to try to locate what remained of the asteroid.

An extensive ground search turned up 47 meteorite fragments for analysis.

"This asteroid was made of a particularly fragile material that caused it to explode at a high 37km (23 miles) altitude, before it was significantly slowed down," said Dr Jenniskens.

"This was a meteorite that was not in our collection, a completely new material."

'Unique'

The report's co-author, Douglas Rumble of the Carnegie Institution, said many meteorites had been observed before as they burned up on entering the Earth's atmosphere.

"It's been happening for years," he said. "But to actually see this object before it gets to the Earth's atmosphere and then follow it in, that's the unique thing."

When meteorites that have fallen to Earth are studied, researchers rarely have direct information of where the asteroid came from or what type it was.

The researchers studying 2008 TC3 say it was one of a very rare type of meteorite called ureilites, which may have originated from a single parent body.

After comparing the data on the asteroid and the fragments found in Sudan, they say 2008 TC3 may be relatively young, having spent only a few million years in the inner solar system.

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