27 Apr 2015

Olivine should be one of the most abundant minerals on asteroid Vesta, but it remains elusive. Scientists working on NASA’s Dawn mission to Vesta were initially thrilled to find few scattered remains of this enigmatic mineral as evidence for telltale signs of planetary differentiation. However, a new Icarus paper by PSI researcher Lucille Le Corre says that at least some of this olivine might not have come from Vesta, but instead was delivered by other asteroids.
The results come in light of a new analysis of data provided by Dawn suggesting that some of the olivine on Vesta may have resulted from olivine-rich meteorites impacting the body rather than being the product of internal geologic activity.
“The lack of abundant olivine on Vesta does not mean that it is not differentiated, as all evidence points to a Vesta that once had crust, mantle and a core,” Le Corre said. “We just need to update our planetary formation models in light of new results from Dawn.”
Above, figures from Thangjam et al. (2014) showing the olivine-rich units in Framing Camera images in Arruntia (A) and Bellicia (B) craters. They inferred more than 60 percent olivine was present in the regolith. Exposures were from few hundred meters to few kilometers.