[P-PS03] 太陽系小天体：太陽系進化における最新成果と今後の展望

[PPS03-17] Current status of DESTINY+ project and science

*荒井 朋子¹、小林 正規¹、石橋 高¹、木村 宏¹、平井 隆之¹、洪 鵬¹、岡本 尚也¹、山田 学¹、千秋 博紀¹、和田 浩二¹、吉田 二美²、Srama Ralf³、クルーガ ハラルド⁴、佐々木 晶⁵、薮田 ひかる⁶、石黒 正晃⁷、関口 朋彦⁸、渡部 潤一⁹、伊藤 孝士⁹、大坪 貴文⁹、阿部 新助¹⁰、大塚 勝仁¹¹、浦川 聖太郎¹²、中村 智樹¹³、廣井 孝弘¹⁴、松浦 周二¹⁵、伊藤 元雄¹⁶、山口 亮¹⁷、小松 睦美¹⁸、中村メッセンジャー 圭子¹⁹、三河内 岳²⁰、橘 省吾²⁰、諸田 智克²⁰、平田 成²¹、出村 裕英²¹、小松 吾郎²²、野口 高明²³、金田 英宏²⁴、紅山 仁²⁰、巽 瑛理²⁵、マーシャル ショーン²⁶、中藤 亜衣子²⁷、矢野 創²⁷、吉川 真²⁷、山本 高行²⁷、尾崎 直哉²⁷、豊田 裕之²⁷、西山 和孝²⁷、今村 裕志²⁷、高島 建²⁷ (1.千葉工業大学惑星探査研究センター、2.産業医科大学、3.シュツッツガルト大学、4.マックスプランク研究所、5.大阪大学、6.広島大学、7.ソウル大学、8.北海道教育大学、9.国立天文台、10.日本大学、11.東京流星観測網、12.日本スペースガード協会、13.東北大学、14.ブラウン大学、15.関西学院大学、16.海洋研究開発機構、17.国立極地研究所、18.総合研究大学院大学、19.NASA Johnson Space Center、20.東京大学、21.会津大学、22.ダヌンツィオ大学、23.京都大学、24.名古屋大学、25.カナリア天文物理学研究所、26.アレシボ天文台、27.宇宙航空研究開発機構)

キーワード：デスティニープラス、小惑星フェートン、ふたご座流星群、フライバイ

DESTINY⁺ (Demonstration and Experiment of Space Technology for INterplanetary voYage with Phaethon fLyby and dUst Science) was selected in 2017 as a mission for JAXA/ISAS small class program. It will be launched in 2024 by an Epsilon S rocket and flyby Phaethon in January, 2028. It is a joint mission of technology demonstration and scientific observation. The engineering mission is led by ISAS/JAXA and the science mission is led by PERC, Chiba Inst. of Technology (ChiTech). It will test high performance electric propelled vehicle technology and high-speed flyby of asteroid (3200) Phaethon and possibly asteroid 2005UD, a likely break-up body from Phaethon, as an extended mission. Engineering challenges include an up-close encounter at a distance of 500 km from Phaethon with radio-optical hybrid navigation guidance and control, and autonomous imaging based on optical information for target tracking during a high-speed flyby of 36 km/sec. The science goal is to understand the nature and origin of cosmic dust brought onto the Earth, in the context of exogenous contribution of carbon and organics for possible prebiotic seeds of the terrestrial life. Phaethon is a parent body of Geminid meteor shower, and thus a known source to periodically provide dust to the Earth, via its dust stream. The science objectives are two folded: (1) in-situ analyses of velocity, arrival direction, mass and chemical composition of interplanetary and interstellar dust particles around 1 au, the dust trail, and nearby Phaethon, and (2) flyby imaging of Phaethon to study its geology, for understanding dust ejection mechanism of active asteroid and the surface feature and composition which are affected by extensive solar heating. Science payloads include a panchromatic, telescopic camera with a tracking capability (TCAP), a visible-NIR multi-band camera with four bands of 425, 550, 700, 850 nm (MCAP), and a dust analyzer (DDA), which is an upgrade version of Cassini Cosmic Dust Analyzer (CDA). While the two cameras are developed by PERC/Chitech, DDA is developed by Univ. of Stuttgart, as an international collaboration with DLR. Ground calibration for DDA is being performed with German/Japanese joint efforts. International observation campaign for Phaethon was conducted in December 2017, and that of asteroid 2005 UD in October, 2018. Also, international observation campaign for stellar occultation by Phaethon was performed in 2019. Continuing efforts to better define the size, shape and albedo of Phaethon have been performed in 2021. Observation of stellar occultation by Phaethon was successfully conducted in the southwestern part of Japan Main Island and the southern part of South Korea in Oct. 4^th, 2021. Photometric observation was conducted by the SEIMEI Telescope of Kyoto University and in JAXA Bisei Space Guard Center from October to November with small solar phase angles. Polarimetric observation was performed in Nishi-Harima Observatory and Higashi Hiroshima Observatory from October through late December with small solar phase angles. Here, we present the current status of DESTINY⁺ project and its science.