* Astronomy

Title: Records of sunspot and aurora activity during 581-959 CE in Chinese official histories in the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms
Author: Harufumi Tamazawa, Akito Davis Kawamura, Hisashi Hayakawa, Asuka Tsukamoto, Hiroaki Isobe, Yusuke Ebihara

Recent studies of radioisotopes in tree rings or ice cores suggest that extreme space weather events occurred in the pre-telescope age. Observational records of naked-eye sunspots and low-latitude auroras in historical documents in pre-telescopic age can provide useful information on past solar activity. In this paper, we present the results of a comprehensive survey of records of sunspots and auroras in Chinese official histories from the 6th century to the 10th century, in the period of Sui, T'ang, the Five Dynasties and Ten Kingdoms. These official histories contain records of continuous observations with well-formatted reports conducted under the policy of the government. A brief comparison of the frequency of observations of sunspots and auroras with the observations of radioisotopes as an indicator of solar activity during the corresponding periods is provided. Based on our data, we survey and compile the records of sunspots and auroras in historical documents from variouslocations and in several languages, and ultimately provide these as open data to the scientific community.

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