Sulfide minerals bear witness to impacts across the solar system

Abstract

Sulfide minerals are ubiquitous in extraterrestrial sample collections and serve as a unique record of the microstructural and chemical characteristics resulting from exposure to interplanetary space on airless planetary surfaces. Among these features are Fe-rich whiskers, identified in samples returned from asteroids and the Moon. While whisker production has previously been attributed to solar wind irradiation, the origin of these enigmatic features is poorly constrained. Here we perform in situ heating experiments to simulate micrometeoroid bombardment of sulfide minerals in the transmission electron microscope. Our results demonstrate that whiskers can form through impact events on airless surfaces and show that sulfides are recording evidence for micrometeoroid bombardment across the solar system. This work contributes to a better understanding of sulfur-depletion previously detected on asteroid surfaces and could be particularly important for the interpretation of data from upcoming missions to sulfide or metal-rich worlds, including asteroid Psyche.