[P-PS03] 太陽系小天体：太陽系の形成と進化における最新成果と今後の展望

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

*荒川 創太¹、鎌田 俊一²、玄田 英典³ (1.海洋研究開発機構、2.北海道大学、3.東京科学大学)

キーワード：太陽系外縁天体、衛星

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.