Japan Geoscience Union Meeting 2025

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[E] Poster

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

Fri. May 30, 2025 5:15 PM - 7:15 PM Poster Hall (Exhibition Hall 7&8, Makuhari Messe)

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


5:15 PM - 7:15 PM

[PPS03-P01] Thermal and Orbital Evolution of Satellite Systems around Undifferentiated Trans-Neptunian Objects: Orcus−Vanth and Salacia−Actaea

*Sota Arakawa1, Shunichi Kamata2, Hidenori Genda3 (1.Japan Agency for Marine-Earth Science and Technology, 2.Hokkaido University, 3.Institute of Science Tokyo)

Keywords:Trans-Neptunian objects, Satellites

Satellites play a crucial role in understanding the formation and evolution of trans-Neptunian objects (TNOs). The spin−orbit evolution of satellite systems depends on their thermal histories, allowing us to constrain the rock mass fraction within TNOs based on their current spin−orbit states. In this study, we perform coupled thermal−orbital evolution calculations for two satellite systems around undifferentiated TNOs: Orcus−Vanth and Salacia−Actaea. Our results demonstrate that the current spin−orbit states of these systems are consistent with a rock mass fraction of approximately 20−30%. Additionally, we estimate the organic mass fraction within the TNOs and find that it is comparable to the rock mass fraction. These findings suggest that the chemical composition of TNOs closely resembles that of comets.