Collisional heating and compaction of small bodies: Constraints for their origin and evolution

Martin Jutzi, Patrick Michel

Icarus
Available online 5 June 2020, 113867

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“Highlights

• We study the degree of collisional heating and compaction by analysing a large set of simulations of break-ups of small bodies in the 50 – 400 km size range
• We find that the degree of impact processing is generally larger than found in previous studies which considered smaller objects (1- 10 km)
• There is a clear dichotomy in terms of impact processing: the escaping material always experiences stronger heating than the material bound to the largest remnant, even in catastrophic disruptions
• Our results provide constraints for the origin and initial properties of small bodies”

“The current properties of small bodies provide important clues to their origin and history. However, how much small bodies were processed by past collisions and to what extent they retain a record of processes that took place during the formation and early evolution of the Solar System is still poorly understood. Here we study the degree of collisional heating and compaction by analysing the large set of previous simulations of small body break-ups by Jutzi et al. (2019), which used porous targets of 50–400 km in diameter and investigated a large range of impact velocities, angles as well as energies. We find that the degree of impact processing is generally larger than found in previous studies which considered smaller objects (e.g. Jutzi et al., 2017; Schwartz et al., 2018). However, there is a clear dichotomy in terms of impact processing: the escaping material always experiences stronger heating than the material bound to the largest remnant. Assuming they originate from the same parent body, some of the observed differences between the recently visited asteroids Ryugu and Bennu may be explained by a different location of the material eventually forming these asteroids in the original parent body. Our results also provide constraints on the initial size of cometary nuclei.”