Investigation of the Solar System Evolution based on Trans-Neptunina Objects

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K13607
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 17010:Space and planetary sciences-related
• Research Institution: National Astronomical Observatory of Japan
• Principal Investigator: Terai Tsuyoshi 国立天文台, ハワイ観測所, RCUH職員 (20624018)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 太陽系小天体 / 太陽系外縁天体 / サイズ頻度分布 / すばる望遠鏡 / サーベイ観測 / 木星トロヤ群 / ヒルダ群小惑星

Outline of Final Research Achievements

We established a method for accurately measuring the size frequency distribution of small-body population in our solar system based on wide survey data obtained by using the Hyper Suprime-Cam, a wide-field imaging instrument mounted on the Subaru Telescope. Using this technique, we successfully determined the size frequency distribution of the primordial population of trans-Neptunian objects (TNOs) in the size range around 100 km in diameter. We also measured the size frequency distributions of Jupiter Trojan and Hilda asteroids, and found that they have the common shape of size distributions but it is distinct from that of main-belt asteroids. These results indicate that Jupiter Trojan and Hilda asteroids have similar origins to that of the dynamically-hot population of TNOs that are considered to have formed in the giant planet regions rather than that of main-belt asteroids.

Free Research Field

惑星科学

Academic Significance and Societal Importance of the Research Achievements

本結果は、太陽系初期における微惑星形成、惑星成長、およびその後に起こったと考えられている惑星大移動とそれに伴う小天体の大規模力学進化を理解するうえで重要な手掛かりを与え得る。本研究課題を発展させる必要性があることは明白で、今度さらなる観測研究を推し進めることが求められる。また、将来の大型地上望遠鏡や宇宙望遠鏡、宇宙探査機による観測・探査方針の策定などへの貢献も期待される。