Revisiting Carrington event with archival materials: Spatiotemporal Evolutions of a Large Sunspot Group and Great Auroral Storms

T he Carrington event (1/2 September 1859) is arguably considered one of the most extreme space weather events in observational history within a series of magnetic storms caused by extreme interplanetary coronal mass ejections (ICMEs) from a large and complex active region (AR) emerged on the solar disk, which hosted probably the earliest and the brightest flare in the observational history. In this presentation, we study the temporal and spatial evolutions of this source sunspot AR and the subsequent visual aurorae, and compare this storm with other extreme space weather events with respect to their their auroral spatial evolution, on the basis of Hayakawa et al. (2019). Original sunspot drawings by multiple contemporary observers including Carrington are analyzed to describe the position and morphology of the source AR at that time. Visual auroral reports from the Russian Empire, Iberia, Ireland, Oceania, and Japan fill the existing spatial gap of auroral visibility and revise the time series of auroral visibility in mid to low magnetic latitudes. The revised time series is compared with magnetic measurements and shows their fair correspondences. The spatial evolution of the auroral oval is compared with those of other extreme space weather events in February 1872, September 1909, May 1921, and March 1989 as well as their storm intensity. This comparison contextualizes the Carrington event certainly within one of the most extreme space weather events, but likely not unique.