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Lifetimes and Emergence/Decay Rates of Star Spots on Solar-type Stars Estimated by Kepler Data in Comparison with Those of Sunspots
Kosuke Namekata, Hiroyuki Maehara, Yuta Notsu +7
Active solar-type stars show large quasi-periodic brightness variations caused by stellar rotations with star spots, and the amplitude changes as the spots emerge and decay. The Ke…
Low-Latitude Aurorae during the Extreme Space Weather Events in 1859
Hisashi Hayakawa, Yusuke Ebihara, David P. Hand +4
The Carrington storm (September 1/2, 1859) is one of the largest magnetic storms ever observed and it has caused global auroral displays in low-latitude areas, together with a seri…
Sporadic Aurora near Geomagnetic Equator: In the Philippines, on 27 October 1856
Hisashi Hayakawa, José. M. Vaquero, Yusuke Ebihara
While low latitude auroral displays are normally considered to be a manifestation of magnetic storms of considerable size, Silverman (2003, JGR, 108, A4) reported numerous "sporadi…
A Great Space Weather Event in February 1730
Hisashi Hayakawa, Yusuke Ebihara, José M. Vaquero +9
Aims. Historical records provide evidence of extreme magnetic storms with equatorward auroral extensions before the epoch of systematic magnetic observations. One significant magne…
The Great Space Weather Event during February 1872 Recorded in East Asia
Hisashi Hayakawa, Yusuke Ebihara, David M. Willis +9
The study of historical great geomagnetic storms is crucial for assessing the possible risks to the technological infrastructure of a modern society, caused by extreme space-weathe…
Sunspot Drawings by Japanese Official Astronomers in 1749-1750
Hisashi Hayakawa, Kiyomi Iwahashi, Masashi Fujiyama +7
Sunspot observations with telescopes in 18th century were carried out in Japan as well. One of these sunspot observations is recorded in an account called Sansaizusetsu narabini Ka…