Condensed-Matter Physics & Materials Science Seminar

A wide range of astrophysical processes, from condensation of dust particles in circumstellar envelopes to space weathering on airless bodies, are inherently pico-to-nanoscale phenomena. Thus an electron microscope, used for direct observation of planetary materials in the laboratory, can be as much of an astronomical tool as a telescope pointed at the sky. The energy resolution of state-of-the-art monochromated scanning transmission electron microscopes (STEMs), as low as 10 meV, makes it possible to directly observe the infra-red optical properties of individual cosmic dust grains in the 5 to 25 um range. Thus, distinguishing the 10-um and 18-um features of individual bonafide astrosilicates is now possible. The identity of volatiles, trapped in individual nanoscale vesicles, can be determined with STEM-EELS to better constrain space weathering processes in lunar soils. Finally, STEM-EDS offers to possibility of constraining noble gas contents of primitive carbonaceous materials, including nanodiamond, and "phase Q", thus thus constrain their formation histories.