Westa na Bennu BY KRZYSZTOF KANAWKA ON 23 WRZEŚNIA 2020
(...) Na Bennu wykryto sześć głazów, które są znacznie jaśniejsze od innej materii tej planetoidy. Obserwacje spektroskopowe wykazały, że w tych głazach znajdują się pirokseny – minerały które wykryto na Weście i mniejszych planetoidach związanych z Westą. (...)
https://kosmonauta.net/2020/09/westa-na-bennu/NASA’s OSIRIS-REx to Asteroid Bennu: “You’ve got a little Vesta on you…”Sept. 21, 2020
During spring 2019, NASA’s OSIRIS-REx spacecraft captured these images, which show fragments of asteroid Vesta present on asteroid Bennu’s surface. The bright boulders (circled in the images) are pyroxene-rich material from Vesta. Some bright material appear to be individual rocks (left) while others appear to be clasts within larger boulders (right).
Credits: NASA/Goddard/University of Arizona(...) Of course it’s possible that the boulders actually formed on Bennu’s parent asteroid, but the team thinks this is unlikely based on how pyroxene typically forms. The mineral typically forms when rocky material melts at high-temperature. However, most of Bennu is composed of rocks containing water-bearing minerals, so it (and its parent) couldn’t have experienced very high temperatures. Next, the team considered localized heating, perhaps from an impact. An impact needed to melt enough material to create large pyroxene boulders would be so significant that it would have destroyed Bennu's parent-body. So, the team ruled out these scenarios, and instead considered other pyroxene-rich asteroids that might have implanted this material to Bennu or its parent.
Observations reveal it’s not unusual for an asteroid to have material from another asteroid splashed across its surface. Examples include dark material on crater walls seen by the Dawn spacecraft at Vesta, a black boulder seen by the Hayabusa spacecraft on Itokawa, and very recently, material from S-type asteroids observed by Hayabusa2 at Ryugu. This indicates many asteroids are participating in a complex orbital dance that sometimes results in cosmic mashups. (...)
https://www.nasa.gov/feature/goddard/2020/bennu-vesta-meteorites