Are the Brighter Rocks on Bennu Products of Recent Mechanical Weathering, and Therefore Less Space-Weathered?

Keller, Lindsay P ; Clark, B E

关键词: AEROSPACE ENVIRONMENTS;    ALBEDO;    ASTEROIDS;    BENNU ASTEROID;    BRIGHTNESS;    EJECTION;    ROCKS;    SPACE WEATHERING;    WEATHERING;   

RP-ID  :  JSC-E-DAA-TN73875

学科分类：天文学(综合)

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

Our hypothesis is that the higher-albedo rocks on the surface of Bennu are products of thermal/mechanical weathering. If this suggestion is correct, then the higher albedo (~7–15%) of some rocks relative to the average background on Bennu (~4.5%) could be explained by their relatively fresh surfaces. Older rocks on Bennu would then be the darkest rocks— those that have experienced the most space weathering over time due to exposure to the space environment. Thermal/mechanical weathering (cracking of rocks) is a candidate mechanism for the particle ejection events observed to occur with regular frequency from the asteroid surface.