date: 2011 June 29 (Wed) 15:00-16:00
room: Hokkaido University, Science Bldg. #8, Cosmo-studio
speaker: Chikatoshi Honda (University of Aizu)
organizer: Jun Kimura
title: Retention time of crater ray materials on the Moon
abstract: Fresh lunar impact craters have rays which are bright features radially expanding from host craters (primary crater). It has been suggested that the rays are erased by space weathering that alters surface materials by exposure to solar wind and micrometeorite bombardments, and by impact gardening that mixes surface materials and subsurface materials by meteorite bombardments (Wilhelms, 1987).
We surveyed craters from 300 m to 10 km in diameter in lunar highland with MI and TC images, and measured the OMAT profiles each crater. The craters that the OMAT value at the crater rim is clearly higher than background OMAT value are detected as rayed craters. We described the size-frequency distribution of the detected craters. The craters larger than 1 km in diameter are plotted above the 750 Ma isochron (Werner and Medvedev, 2010).