* Astronomy

Title: Discovery of coesite and stishovite from eucrite
Authors: M.MIYAHARA, E.OHTANI, A.YAMAGUCHI, S. OZAWA, T.SAKAI AND N.HIRAO

The existence of a high-pressure polymorph in a meteorite is a critical evidence for a dynamic event occurred on its parent-body. It is expected that HEDs meteorites originate from an asteroid, 4 Vesta. Although recent Dawn mission clarified that 4 Vesta suffered from heavy meteorite bombardments, a high-pressure polymorph has not been found in HEDs meteorites so far. We got one of eucrite samples, Béréba. Béréba sample studied here has several shock-melt veins, implying that it was heavily shocked. We investigated Béréba using a laser micro-Raman spectroscopy, FEG-SEM and FIB-TEM techniques to clarify a record of a dynamic event and its possible parent-body.

Read more (PDF)