Comets and Asteroids

Implantation Of Asteroids From The Terrestrial Planet Region: The Effect Of The Timing Of The Giant Planet Instability

By Keith Cowing
Status Report
April 24, 2024
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Implantation Of Asteroids From The Terrestrial Planet Region: The Effect Of The Timing Of The Giant Planet Instability
Final distributions of planets at 𝑡 = 200 Myr, in four sets of simulations with different instability times. The timing of the instability is indicated at the top of each panel, relative to the time of the gas disk dispersal. Each panel shows the results of simulations considering rings with different radial surface density profiles. The x-axis shows planets’s semi-major axis. The y-axis shows the planets’ mass. Light-grey dots show planets produced in our simulations. The four dark-grey dots represent the real terrestrial planets. The giant planet dynamical instability is mimicked by assuming that Jupiter and Saturn instantaneously jump from their pre-instability orbits to their current ones at 𝑡 = 𝑡 inst.– astro-ph.EP

The dynamical architecture and compositional diversity of the asteroid belt strongly constrain planet formation models.

Recent Solar System formation models have shown that the asteroid belt may have been born empty and later filled with objects from the inner (<2~au) and outer regions (>5 au) of the solar system. In this work, we focus on the implantation of inner solar system planetesimals into the asteroid belt – envisioned to represent S and/or E- type asteroids – during the late-stage accretion of the terrestrial planets.

It is widely accepted that the solar system’s giant planets formed in a more compact orbital configuration and evolved to their current dynamical state due to a planetary dynamical instability.

In this work, we explore how the implantation efficiency of asteroids from the terrestrial region correlates with the timing of the giant planet instability, which has proven challenging to constrain. We carried out a suite of numerical simulations of the accretion of terrestrial planets considering different initial distributions of planetesimals in the terrestrial region and dynamical instability times.

Our simulations show that a giant planet dynamical instability occurring at t⪆5 Myr — relative to the time of the sun’s natal disk dispersal — is broadly consistent with the current asteroid belt, allowing the total mass carried out by S-complex type asteroids to be implanted into the belt from the terrestrial region.

Finally, we conclude that an instability that occurs coincident with the gas disk dispersal is either inconsistent with the empty asteroid belt scenario, or may require that the gas disk in the inner solar system have dissipated at least a few Myr earlier than the gas in the outer disk (beyond Jupiter’s orbit).

Andre Izidoro, Rogerio Deienno, Sean N. Raymond, Matthew S. Clement

Comments: Under review in Icarus
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2404.10831 [astro-ph.EP] (or arXiv:2404.10831v1 [astro-ph.EP] for this version)
Submission history
From: Andre Izidoro
[v1] Tue, 16 Apr 2024 18:08:53 UTC (2,664 KB)


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