What Do We Know about Asteroid Regolith? 小行星风化层综述

摘要：Regolith is what we encounter universally on the surfaces of solid bodies, from small asteroids to planets. The term comes from the Greek rhegos (blanket) + lithos (stone). The thickness, texture, particle size, distribution, chemistry, and evolution of regolith depends very much on the geologic context of the body. The creation and depletion of regolith is driven by weathering processes, the thermal environment, the interaction between gravity, cohesion, and the solar wind, the chemistry of the surface, and the energetic environment. The best studied example is the lunar regolith which consists of a very loose, fluffy powder about 20 cm deep overlying a fine-grained and more compact reworked layer that can vary between 4-10 meters in depth. An asteroid regolith will be much different since mineralogy, chemistry, gravity, and impact energies will all be much different. I will review what we know and can infer about asteroid regolith and make some suggestions about what we may encounter on with upcoming sample return missions.

报告人简介: Dr. Daniel Britt is a Professor of Astronomy and Planetary Sciences at the Department of Physics, University of Central Florida. He was educated at the University of Washington (Economics and Geology) and Brown University, receiving a Ph.D. in Geological Sciences from Brown in 1991. He has had a varied career including service as a US Air Force officer and an economist for Boeing before going into planetary sciences. He has served on the science teams of several NASA missions including Mars Pathfinder and Deep Space 1, and has recently joined the New Horizons Mission Science Team for the flyby of the Kuiper Belt asteroid 2014 MU69 and the Lucy Mission Science Team for a series of flybys of asteroids near Jupiter. He was the project manager for the camera on Mars Pathfinder and has built hardware for all the NASA Mars landers. He currently does research on the physical properties and mineralogy of asteroids, comets, the Moon, and Mars under several NASA grants and is the director of the Center for Lunar and Asteroid Surface Science (CLASS), a node of NASA’s Solar System Exploration Research Virtual Institute (SSERVI). He has served as the Chair of the Division for Planetary Sciences of the American Astronomical Society and the Planetary Geology Division of the Geological Society of America. Honors include 6 NASA Achievement Awards, election as a Fellow of the Meteoritical Society, and an asteroid named after him: 4395 DanBritt.