[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-P12] High Degree Products of Thermal Infrared Imager onboard Hayabusa2

*荒井 武彦¹、出村 裕英²、岡田 達明⁴、田中 智⁴、坂谷 尚哉⁴、嶌生 有理⁴、千秋 博紀³、神山 徹⁵、石崎 拓也⁴、金丸 仁明⁷、関口 朋彦⁶ (1.前橋工科大学、2.会津大学、3.千葉工業大学、4.宇宙航空研究開発機構、5.産業技術総合研究所、6.北海道教育大学、7.東京大学)

キーワード：はやぶさ２、中間赤外カメラ、熱慣性、高次プロダクト

The thermal infrared imager (TIR) onboard the Hayabusa2 spacecraft observed the surface temperature of asteroid 162173 Ryugu during 2018 and 2019. TIR derives the surface thermophysical properties and reveals the surface thermal evolution and the origin of their accumulation process. Thermal inertia is a key index for estimating surface thermophysical properties. This index is critical for evaluating the surface's physical condition, such as density and porosity. However, surface roughness under the spatial resolution of TIR confuses the estimation of the thermal inertia. The observed surface brightness temperature of TIR was globally flattened due to the roughness. Therefore, we need a surface thermophysical model, including the roughness model, to derive the accurate thermal inertia. We used the shape model of Ryugu with Gaussian random numbers as the roughness model. We compared the observed image with the anticipated images derived from the thermophysical model with roughness and determined the thermal inertia maps. In this study, we introduce the high-degree products of the TIR data, such as shape model projection maps (Level 3) and thermal inertia maps (Level 4).