Candidate Auroral Observations Indicating a Major Solar-Terrestrial Storm in 1680: Implication for Space Weather Events during the Maunder Minimum

The Maunder Minimum (MM; 1645-1715) is currently considered the only grand minimum within telescopic sunspot observations since 1610. During this epoch, the Sun was extremely quiet and unusually free from sunspots. However, despite a reduced frequency, candidate aurorae were reported in the mid-European sector during this period and have been associated with occurrences of interplanetary coronal mass ejections (ICMEs), although some of them have been identified as misinterpretations. Here, we have analyzed reports of candidate aurorae on 1680 June 1 with simultaneous observations in central Europe, and compared their descriptions with visual accounts of early modern aurorae. Contemporary sunspot drawings on 1680 May 22, 24, and 27 have shown a sunspot. This sunspot may have been a source of ICMEs, which caused the reported candidate aurorae. On the other hand, its intensity estimate shows that the geomagnetic storm during this candidate aurora was probably within the capability of the storms derived from the corotating interaction region (CIR). Therefore, we accommodate both ICMEs and CIRs as its possible origin. This interpretation is probably applicable to a number of candidate aurorae in the oft-cited Hungarian catalog, on the basis of the reconstructed margin of their equatorward auroral boundary. Moreover, this catalog itself has clarified that the considerable candidates during the MM were probably misinterpretations. Therefore, the frequency of the auroral visibility in Hungary was probably lower than previously considered and agrees more with the generally slow solar wind in the existing reconstructions, whereas sporadic occurrences of sunspots and coronal holes still caused occasional geomagnetic storms.

Automated summary

The Maunder Minimum was a period of minimal sunspot activity from 1645 to 1715, but candidate aurorae were still reported, possibly linked to interplanetary coronal mass ejections.