Chelyabinsk meteorite may have gang of siblings – study
Edited time: August 05, 2013 16:13
The Chelyabinsk meteorite that hit Russia in February, injuring over a thousand, may have stemmed from a massive cluster of rocks which broke off from a disintegrating asteroid thousands of years ago, a new study claims.
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: Letters.
The study points out that the shattered pieces of a rubble-pile asteroid can spread along the entire orbit of the parent body, making their collision with Earth possible on a time-scale of hundreds of years.