Abstract

Recent analyses of spectrophotometric data of asteroids 9 Metis and 113 Amalthea have revealed a probable genetic (compositional) link between these two objects. The nearly identical composition of the silicate components of these two asteroids is consistent with their derivation from a single parent body. Based on the present compositional and morphological interpretations of 9 Metis and 113 Amalthea, and using plausible (chondritic) starting compositions for the parent body, the original parent asteroid is estimated to have been between approximately 300 and 600 km in diameter. Thus Metis and Amalthea are the largest survivors of a highly evolved, genetic asteroid family from which 86-96% of the original mass has been lost.