ESRF helps to identify the most promising interstellar candidate found so far


An international team of scientists has identified the two most promising candidates for stardust particles. This breakthrough was presented at the Lunar and Planetary Science Conference in Houston by team leader Andrew Westphal, of the University of California (US) last March.

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 The particles were collected during NASA’s Stardust mission that probed the interstellar stream over a 15 month period. Since 2006 not only scientists, but also amateurs worldwide, have been scanning samples for the needle in the haystack: dust particles from other parts of our galaxy that were carried to our solar system via the interstellar stream. 

A team of researchers from the Goethe-University Frankfurt, the Gent University and the European Synchrotron Radiation Facility joined forces to identify the chemical structure of the particles in a non-destructive way by using ID13, the microfocus beamline. Particle number 30 was subdivided and named Orion and Sirius. These two particles were identified as the most likely interstellar candidates discovered to date. After the successful preliminary analysis and beamtime at the ESRF, the sample went back to the University of California for further studies. Although Westphal stressed that the discovery "could be a false alarm", he added: "So far this particle is unique... if we drop it on the floor, it will cost $300m to get another one". 

The samples will come back to the ESRF for further investigations. Because of the positioning of the possible interstellar particles (one behind the other), researchers could not have the full picture of their composition in their first examination. If this future work on the particles confirms their interstellar nature, the ESRF would be the place where the first chemical data of a contemporary interstellar particle was ever collected.

Top image: A typical wedge shaped slice of aerogel from the Stardust mission containing a high speed impact track of a capture extraterrestrial particle. Credit: NASA/JPL-Caltech/University of California, Berkeley.