Star dust in Antarctica

This artist’s impression shows dust forming in the environment around a supernova explosion.

Scientists have found particles of a rare isotope of iron (Fe-60) in Antarctica snow, which they believe could have originated from nearby supernovae. This, they say, could help us understand the structure and origin of interstellar dust clouds.

The team, led by Dominik Knoll of Australian National University, collected 500 kg of “fresh” (less than 20 years old) Antarctic snow, melted it and analysed the isotopes it contained.

The analysis showed the presence Fe-60. After eliminating the possibility of terrestrial sources, such as nuclear power plants and nuclear weapons, the team concluded that the isotope must have come from interstellar dust, where it was forged by a nearby supernova that produced clouds of gas and dust enriched with radioisotopes. The scientists have conjectured that as the solar system passed through such clouds in the past, this dust fell on the earth’s surface, where detectable concentrations of it have accumulated.

The finding could help pin down the source of the dust more precisely and reveal the history of the solar system’s interactions with its interstellar environment. The findings have been published in the latest issue of “Physical Review Letters”.