W wyniku badań próbek z Itokawy stwierdzono, że doświadczyła ona transformacji wywołanej impaktem przed 2,1 mld lat temu.
Samples brought back from asteroid reveal ‘rubble pile’ had a violent pastMEDIA RELEASE Wednesday 18 October 2017
(...) Lead author of the study, Associate Professor Fred Jourdan from the Department of Applied Geology within the Curtin WA School of Mines, explained Itokawa was no ordinary asteroid, with fly-by pictures taken by Hayabusa prior to sampling in 2005 showing it had a peanut-like shape and resembled a rubble pile of boulders and dust more than solid rock.
“In fact, analyses by Japanese scientists revealed the asteroid had a violent past. Prior to being a rubble pile, Itokawa was part of a much larger asteroid that was destroyed by a collision with another asteroid. Our job was to try to find out when that collision happened,” Dr Jourdan said.
Dr Jourdan explained that the analyses were not without challenges, due to the extremely small size of the particles.
“Using our noble gas mass spectrometer at Curtin University, a revolutionary new machine that we customised for extra-terrestrial samples, we were able to measure tiny amounts of gas and analyse these fragments from Itokawa,” Dr Jourdan said.
“The impact-shocked particle indicated a small-scale collision that occurred 2.1 billion years ago, whereas the other non-shocked particle preserves a very old age, similar to the formation age of the solar system itself.”According to these results and a series of models, the scientists concluded that asteroids do not always break up due to a single cataclysmic impact. Instead, they can internally fragment due to the medium-sized collisions that constantly batter large asteroids until they shatter from impact.
“The final impact could be seen as ‘the straw that broke the camel’s back’,” Dr Jourdan said. (...)
http://news.curtin.edu.au/media-releases/samples-brought-back-asteroid-reveal-rubble-pile-violent-past/
Wątek: Hayabusa (Przeczytany 16995 razy)