Presentation #207.02 in the session Planetary Origins Dynamics Posters.
Giant impacts dominate the final era of accretion in most planet formation models. While expected to lead to planet growth, giant impacts also generate impact ejecta. This debris will go into orbit about the Sun, but will be geologically distinct from the surviving primordial planetesimals already in orbit. Our goals are to investigate how much of this debris may survive from the era of planet formation in the asteroid belt today and how the development of Mars affects the trajectory of debris to the asteroid belt.
In our work, we study the fate of impact ejecta in two common terrestrial planet formation scenarios, defined by the assumed orbits of Jupiter and Saturn during this early era. For each scenario, we ran suites (with multiple runs) of simulations, varied by initial mass distribution and radial separations. In the circular Jupiter and Saturn (CJS) scenario, the giant planets are on compact, circular, and nearly in-plane orbits primed for a Nice model-like giant planet instability. In the eccentric Jupiter and Saturn (EJS) scenario, the giant planets effectively start on their modern day orbits.
Analyzing the final heliocentric distances of the debris particles created in each simulation allows us to quantify how many of them ended up in the asteroid belt. We can then compare these to the other particles created were scattered or lost. Further comparison of the EJS and CJS results can inform whether orbital excitation plays a role in the final position of the debris particles.
We also look at successful simulations i.e those in which a Mars-like planet and two Earth or Venus-like planets are produced to study individual debris particles. We track the time evolution of individual debris particles that end up in the asteroid belt to observe how the particular arrangement of planets affects the efficiency of fragments emplaced in the asteroid belt. Studying results from these scenarios allows for an in-depth understanding of the formation of the terrestrial planets’ effects on the asteroid belt.
Our results demonstrate that 2% of simulated debris ends up in the asteroid belt. Additionally, more debris from CJS simulations ended up in the asteroid belt, which is expected because of the lower initial eccentricity and inclination. We also observed that with later impacts, interactions between Mars and the particle last longer, and as a result, the debris particle may or may not stabilize as it enters the asteroid belt. We can conclude that the final arrangement of the planets in the Solar System, specifically Mars, does in fact affect how debris particles travel to the asteroid belt.