August 5, 2013

Gang of Asteroids: Russian meteor may have followers on same path - Aug 5, 2013

The panic and havoc seen in the Russian Urals last winter when a meteor the size of a house exploded in the skies, may be set for a repeat. Scientists say the huge rock might not have been flying solo as first thought, but rather as part of a group of asteroids which still pose a threat to Earth.

Spanish astronomers have discovered that the Chelyabinsk bolide, an 18-meter wide 11,000-ton space rock that burst in a 460-kiloton explosion above Russia, used to be a part of a larger space body.

Scientists believe between 20,000 to 40,000 years ago, a massive body orbiting the sun broke up, most likely as a result of the temperature extremes and planetary gravitation it experienced while looping out past Mars and Venus.

Subsequently, the pieces of that asteroid formed a so-called ‘asteroid family’, a group of asteroids that share same origin, composition and orbit. The parent of this potentially hazardous asteroid family has been identified as 2011 EO40. Those rocks are still flying somewhere in space, and just like the Chelyabinsk meteorite, their orbits could intersect with that of Earth.

In a new study, Carlos de la Fuente Marcos and his brother Raul from the Complutense University in Madrid said that they have found reliable statistical evidence for the existence of the Chelyabinsk cluster, or asteroid family.

The brothers used computer simulations of billions of possible asteroid orbits to find the ones most fitting into the Chelyabinsk impactor pre-collision orbit. They then searched the NASA database of known asteroids to find out if any of them follow those orbits. In the course of their investigation, they spotted the Chelyabinsk bolide family of about 20 asteroids, which range in size from 5 to 200 meters across.

“It appears to include multiple small asteroids and two relatively large members: 2007 BD7 and 2011 EO40. The most probable parent body for the Chelyabinsk superbolide is [asteroid] 2011 EO40,” according to their article, which is to be published in Monthly Notices of the Royal Astronomical Society.

The Spaniards do admit that the orbits of the Chelyabinsk bolide asteroid family have not been definitively calculated and there is room for debate about whether they are a ‘family’ at all. Still, Carlos de la Fuente Marcos warns, “More objects with the same orbital signature may encounter our planet in the future”. Read more at RT

 

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