Japan Geoscience Union Meeting 2024

Presentation information

[E] Oral

P (Space and Planetary Sciences ) » P-PS Planetary Sciences

[P-PS03] Small Solar System Bodies: New perspectives on the origin and evolution of the Solar System

Tue. May 28, 2024 1:45 PM - 3:00 PM 101 (International Conference Hall, Makuhari Messe)

convener:Ryota Fukai(Japan Aerospace Exploration Agency), Tatsuaki Okada(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Sota Arakawa(Japan Agency for Marine-Earth Science and Technology), Fumi Yoshida(University of Occupational and Environmental Health, Japan), Chairperson:Sota Arakawa(Japan Agency for Marine-Earth Science and Technology), Fumi Yoshida(University of Occupational and Environmental Health, Japan)

2:45 PM - 3:00 PM

[PPS03-15] Revealing the building blocks of the terrestrial planets and the origin of asteroids in the Jupiter-Saturn chaotic excitation (JSCE) model

*Patryk Sofia Lykawka1, Takashi Ito2 (1.Kindai University, 2.National Astronomical Observatory of Japan)

Keywords:solar system , terrestrial planets , asteroid belt , water, Mars , Mercury

The Jupiter–Saturn chaotic excitation (JSCE) scenario offers a plausible explanation for several observed properties of the inner solar system. Still, simultaneously replicating the four terrestrial planets’ orbits/masses, the asteroid belt’s main properties, and other inner solar system constraints remains a tremendous challenge.

Here, we investigated the simultaneous formation of the four terrestrial planets (Mercury, Venus, Earth, and Mars) and the asteroid belt in the context of the JSCE scenario. We found that our terrestrial systems satisfied several inner solar system constraints.

A comprehensive analysis of 37 optimally formed terrestrial planet systems allowed us to constrain the planets’ building blocks, accretion history, and other fundamental properties. First, the obtained terrestrial planets acquired orbits and masses very similar to those observed in our solar system. In addition, other key results include Moon-forming giant impacts occurring within ~60 Myr, terrestrial planets’ bombardment of late impactors represented by disk objects formed within 2 au, and bulk water acquired during the first 10–20 Myr of Earth’s formation. In particular, achieving Earth’s estimated bulk water content required the disk to initially contain sufficient water mass in objects beyond ~1–1.5 au. This requirement implies that Mercury, Venus, and Mars acquired water similar to the amount on Earth during their formation.

Finally, our model asteroid belt explained the asteroid belt’s orbital structure, small mass, and taxonomy (S-, C- and D/P-types). The current asteroids represent a mixture of local asteroids that survived the dynamical depletion of the primordial asteroid belt by JSCE and captured asteroids from trans-Jovian reservoirs during the giant-planet instability/migration.