Probing the Early Solar System Through Coordinated Laboratory Microanalysis of Primitive Astromaterials

Laboratory study of extraterrestrial (ET) materials, including meteorites, micrometeorites, interplanetary dust particles (IDPs), and, increasingly, returned samples, provides a unique glimpse into Solar System formation and early evolution. Samples from undifferentiated asteroids and comets represent a fossil record of the earliest planetary building blocks and can be used to probe the starting materials, physical and chemical conditions, and time scales of processes in the protoplanetary disk and small primitive bodies. Recent developments in micro- and nano- technology have allowed for the increasing ability to probe chemical, isotopic, and morphological properties of the same astromaterials on sub-micrometer scales. We routinely use Nano-scale Secondary Ion Mass Spectrometry (NanoSIMS) to map isotopic ratios with 100-nm resolution to search primitive ET materials for ultra-rare “presolar stardust” — sub-micron dust particles with isotopic compositions pointing to an origin in ancient stars and supernovae — and to map the H. N, and C isotopic composition of carbonaceous matter. Interesting materials can be further extracted for analysis by Transmission Electron Microscopy, laser Raman micro-spectroscopy, and synchrotron transmission X-ray Microscopy. Such studies provide new insights into how elements are produced in stars, how dust is processed in interstellar space, the origin and distribution of organic matter in the Solar System, transport of materials in the protoplanetary disk, and alteration processes (e.g., heating, aqueous alteration) on asteroids billions of years ago. Methods developed for and lessons learned from naturally returned samples (meteorites, IDPs) can be readily applied to samples returned by spacecraft, including the recently returned samples of asteroid Ryugu by JAXA’s Hayabusa2 mission and, in a few years, asteroid Bennu samples collected by NASA’s OSIRIS-ReX.