Hyper-Velocity Impacts on Rubble Pile Asteroids

ISBN-13: 9783319838731 / Angielski / Miękka / 2018 / 164 str.

Jakob Deller

Spis treści

Introduction.- Asteroids and Comets in the Solar System.- The Interior of Asteroids.- Impact Processes in the Solar System.- Simulating Impacts on Rubble Pile Asteroids.- Methods.- Numerical Simulations of Impact Events.- Gravitational Forces in High-Resolution Impact Simulations.- A New Approach to Modelling Impacts on Rubble Pile Asteroid Simulants.- Rubble Pile Asteroid Simulants.- Hydrocode Impact Simulations.- Assessing the Influence of Rubble Pile Structures on Impact

Simulations.- Comparing Outcomes of Simulations.- Results — Sensitivity to Model Parameters.- Summary.- Impacts on Rubble Pile Asteroid Šteins.- Asteroid Šteins.- Šteins as a Rubble Pile Asteroid.- Simulating Crater-Forming Impacts on Asteroid Šteins.- The Influence of Gravitational Forces on Simulated Impacts

on Šteins.- Reproducing Surface Features Observed on Šteins.- Asteroid Šteins: Conclusions.- Discussion.- A Simulant for the Large Scale Structure of Rubble Pile Asteroids.- The Internal Structure of Rubble Pile Asteroids in Impact Events.- Linking Surface Features on Šteins to its Internal Structure.- Šteins as a YORP Evolved Asteroid.- Applicability of the Rubble Pile Interior Model.- Future Applications of the Model.- Bibliography.-

O autorze

Jakob Deller has defended his PhD thesis in September 2015. His PhD project was jointly accompanied and funded by the University of Kent and the Max Planck Institute for Solar System Research, Göttingen. He was awarded the Pierazzo International Student Travel Award by the Planetary Science Institute, Tucson, Arizona, and presented his work in multiple international conferences. He gained observing experience at the NTT at La Silla Observatory, Chile.

He was awarded his M. Sc. in November 2011 with a thesis on the ‘Stability of some recently found circumbinary systems’ supervised by Prof. Dr. S. Dreizler at the Institute for Astrophysics Göttingen, Germany. 

Blurb

The thesis presents a tool to create rubble pile asteroid simulants for use in numerical impact experiments, and provides evidence that the asteroid disruption threshold and the resultant fragment size distribution are sensitive to the distribution of internal voids. This thesis represents an important step towards a deeper understanding of fragmentation processes in the asteroid belt, and provides a tool to infer the interior structure of rubble pile asteroids.

 

Most small asteroids are 'rubble piles' – re-accumulated fragments of debris from earlier disruptive collisions. The study of fragmentation processes for rubble pile asteroids plays an essential part in understanding their collisional evolution. An important unanswered question is “what is the distribution of void space inside rubble pile asteroids?” As a result from this thesis, numerical impact experiments can now be used to link surface features to the internal structure and therefore help to answer this question.

 

Applying this model to asteroid Šteins, which was imaged from close range by the Rosetta spacecraft, a large hill-like structure is shown to be most likely primordial, while a catena of pits can be interpreted as evidence for the existence of fracturing of pre-existing internal voids.