Weathering processes in space are very different from weathering processes on Earth. Instead of being driven by forces such as wind, water, and oxidation, space weathering is driven by ion irradiation by the solar wind and by micrometeorite impacts. These processes drastically change the surfaces of airless bodies such as the asteroid Vesta and can cause difficulties when trying to understand their composition and structure. To address this issue, a team of scientists in China led by Shu-Zhou Wang studied a meteorite from Vesta that contains evidence of space weathering using an array of techniques to better understand the chemical and physical properties of space weathering products.
The team found that the meteorite contains iron-sulfur and iron-nickel compounds that are different from space weathering products found in lunar samples. They suggest that these variations could be due to differences in impact rates or bulk composition between the Moon and Vesta. Furthermore, impact events produce massive quantities of heat that can vaporize sulfur, which will interact with nearby rock and create some unusual textures found in the meteorite. This sulfide replacement reaction could be more common on airless bodies than previously thought and might be found in the samples returned from asteroids Ryugu and Bennu by the Hayabusa2 and OSIRIS-REx spacecrafts. READ MORE