Apr 122012

Sand storms in space have been discovered by astronomers watching the death-throes of giant stars. Three ‘red giants’ were observed having their atmospheres ripped away by a ‘superwind’ containing dusty grains of silica. 

SandstormAstronomers have discovered sandstorms in space after using state-of-the-art techniques to search the atmospheres of distant, dying stars.  Superwinds carrying the dust that can travel up to 20,000 miles an hour have been observed travelling around three red giants in the Milky Way.


The grains were unexpectedly large in size for stellar wind particles, measuring almost a micrometer across. They were driven into space by starlight at rocket-velocity speeds of around 20,000 mph (more than 32,000 kilometers per hour). The discovery, made by astronomers using the European Southern Observatory’s Very Large Telescope in Chile, is reported in the journal Nature.

Scientists previously knew that many stars end their lives with a ‘superwind’ that removes as much as half of their mass over a period of around 10,000 years. Eventually only a dying and fading remnant of the star is left.

The Sun will start to undergo this fatal process in around five billion years after expanding in size to become a red giant.

Superwinds were thought to be driven by tiny dust grains, but how the mechanism works has been a mystery. Computer simulations suggested that the dust grains would evaporate before being ejected by a star. But the new observations suggest they are big enough to reflect starlight instead of absorbing it, and to avoid being destroyed.

Lead scientist Professor Albert Zijlstra, from the University of Manchester’s Jodrell Bank Observatory, said: ‘The dust and sand in the superwind will survive the star and later become part of the clouds in space from which stars form. ‘The sand grains at that time become the building blocks of planets. Our own Earth has formed from star dust. We are now a big step further in understanding this cycle of life and death.’

Source: The Daily Mail/Mail Online


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