摘要：Space weathering is a generic term for the effects on atmosphereless solid bodies in the solar system from a range of processes associated with direct exposure to the space environment. These include impact processes (shock, vaporization, fragmentation, heating, melting, and ejecta formation), radiation damage (from galactic and solar cosmic rays), solar wind effects (irradiation, ion implantation, and sputtering), and the chemical reactions driven by these processes (reduction, formation of carbon compounds, catalysis). The classic example of space weathering is the formation of the lunar spectral red slope associated with the production of nanophase Fe (npFe0) in the dusty lunar regolith. Similar npFe0 has been recovered from asteroid 25143 Itokawa and some asteroid classes do exhibit modest spectral red slopes. This impressive array of processes makes it difficult to see the overall driving forces behind space weathering. I will review weathering processes, their effects on surface physical properties, their spectral effects, and propose a simple theory of space weathering.

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.