[P-EM17] 宇宙天気・宇宙気候

[PEM17-P18] Phesant tail aurora: The oldest record of astronomical phenomenon in Japan

*片岡 龍峰¹、山本 和明²、藤原 康徳¹、塩見 こずえ¹、國分 亙彦¹ (1.国立極地研究所、2.国文学研究資料館)

The oldest record of an astronomical phenomenon in Japan was recorded in the Nihon-shoki as follows: "On December 30 in 620, a red sign appeared in heaven. The length was more than 1 jo (10 degrees). The shape was similar to a pheasant tail (Suiko-Tennou, 28)". The appearance of a red sign has been recognized as an expression of a bad omen in literature, while it has been interpreted as the northern lights in geophysics. We introduce the latest scientific findings that the northern lights show a fan-shaped appearance with a red background when appearing over Japan (Kataoka et al., 2019). After showing that the fan-shape is similar to a pheasant tail, also pointing out the low possibility of comets, we conclude that the oldest record of the red sign is consistent with the appearance of the northern lights over Japan.

Reference:
Kataoka, R., S. Uchino, Y. Fujiwara, S. Fujita, and K. Yamamoto (2019), Fan-shaped aurora as seen from Japan during a great magnetic storm on 11 February 1958, 9, A16, https://doi.org/10.1051/swsc/2019013.