Researchers detect radioactive interstellar dust in the Antarctic Ice

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Kohnen-Station
Kohnen Station, where the radioisotopes have been detected. (Credits - Wikimedia Commons)

In new research, scientists have found evidence of dust from a nearby supernova under several thousand pounds of Antarctic snow. Our solar system not only comprises of celestial objects such as planets, moon, sun but also a lot of dust that might have originated from the interstellar sources. A group of researchers in Germany, Austria and Australia is in the search of the presence of dust on Earth to understand the circumstances in which the solar system is moving forward. The study has been published in the Physical Review Letters. 

Dominik Koll, first author of the study and a PhD candidate from Australian National University mentioned he is very excited to learn about the stellar explosions and structures present around our planet which have faraway origins. Scientists transported fresh snow which is not more than 20 years old, weighing almost 1100 pounds from the Kohnen Station located in Antarctica to Munich, Germany.

Then the snow was melted in the laboratory, filtered and evaporated for collecting dust and other micrometeorites. Dust was incinerated and put into Accelerator Mass Spectrometer. It is used to create charged ions from the sample, pass through the magnet and then into a particle accelerator before finally sending to a detector. This technique is useful for collecting only specific atomic isotopes. 

The team wanted to find iron-60, a radioactive isotope released by the supernova. It can also have other sources such as the matter irradiated by the cosmic rays. For guaranteeing it to be interstellar dust, researchers also searched for manganese-53 and compared the ratio of iron-60 to manganese-53 to the ratio expected if there was no presence of interstellar dust. A lot more iron-60 was found than expected from the cosmic rays. 

Thomas Faestermann, TU Munich explained that it was previously established that iron-60 was deposited in the solar system by a nearby supernova in the past 1.5 to 3 million years. Its prolonged presence on Earth indicates it is coming from a remaining dust cloud from a supernova.

These studies show better conditions of the interstellar environment through which Sun is travelling. It has been detected that the Sun is in a “Local Bubble” where the density of the interstellar medium is quite less than average possibly due to a recent supernova. It contains the Local Interstellar Cloud which has a higher density than the Bubble. We can know more about these regions from the dust found in Antarctica. 

There are lots of findings remaining as the Antarctic ice could lead an exposition of the history of an ancient supernova. 

Journal Reference: Physical Review Letters. 

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