A long-standing mystery about how dying stars spew out the material of future planets is now solved, scientists say.
While stars like our Sun are known to eject much of their mass in their final years, it has remained unclear just how the dust is blown away.
Scientists reporting in Nature describe an astronomical study of extraordinary resolution to tackle the mystery.
They found dust grains of nearly a millionth of a metre across, big enough to be pushed out by dying stars' light.
The team of astronomers from Australian and European universities took a look at three so-called red giant stars - stars that were once like our Sun is now, but that have exhausted their supply of hydrogen and grown to gargantuan proportions.