[M-ZZ40] プラネタリーディフェンス-国際的な取り組みと協力

[MZZ40-12] Japan's activities to asteroid 2024 YR4 that could collide with Earth

*吉川 真¹、竹内 央¹、浦川 聖太郎⁴、寺居 剛²、吉田 二美³ (1.宇宙航空研究開発機構、2.国立天文台、3.産業医科大学、4.日本スペースガード協会)

キーワード：プラネタリーディフェンス、小惑星、観測、軌道解析

IAWN (International Asteroid Warning Network) announced on January 29, 2025 that asteroid 2024 YR4, whose first observation report was made on December 27, 2024, has a 1.3% chance of colliding with the Earth on December 22, 2032. This asteroid is estimated to be between 40 and 90 meters in size, and if it were to collide with Earth, it could cause damage similar to the Tunguska explosion that occurred in Siberia, Russia in 1908. It has a value of 3 on the Torino scale, which is an indicator of the degree of alertness for a celestial body collision, so there is no need for the general public to take any immediate action, but those who can observe it are encouraged to observe this asteroid and improve the accuracy of orbit estimation. However, as of mid-February 2025, it is faint at about 24 mags, and observation with large telescopes or the James Webb Space Telescope is desired. What we should do for this asteroid in terms of planetary defense is being discussed not only by IAWN but also by the Space Mission Planning Advisory Group (SMPAG), and Japan is also hurriedly considering and working on observations using the Subaru Telescope, searching to see if this asteroid has been photographed in past observations, and analyzing its orbit. These works are ongoing at the time of writing this abstract, and the results will be reported.