Exposure ages and dynamical models of meteorite delivery

Exposure ages and dynamical models of meteorite delivery 

Here we discuss constraints imposed by the observed distributions of exposure ages 

Even though meteorites may be brought to Earth quickly from within a resonance in the main belt, it is not clear whether the 0.2-Myr peak of the CM chondrites can be explained this way. This would require a very large collision on a CM parent body in a position where the time needed to drift into a resonance would be extremely short and from which we would see today perhaps just some forerunners. It appears more likely that the 0.2 Myr CM chondrites are the products of a collision on a parent body already on an orbit crossing that of the Earth (Caffee and Nishiizumi 1997). 

meteorites with a complex exposure history may help us to constrain collisional dynamics in the asteroid belt, the dynamics of asteroidal regoliths, and perhaps the energetic particle environment in the early solar system. On the other hand, we mentioned above that complex exposure histories often hinder our efforts to determine exposure age distributions. 

1999) and is therefore expected to show effects of pre-exposure in the parent body regolith. Polnau et al. (2001) therefore suggest that the chondrules in the other meteorites may have experienced exposure in a very high flux of solar energetic particles in the early solar system. This conclusion deserves further verification, especially by meteorites with very short exposure ages. 

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