Graphical evidence for the solar coronal structure during the Maunder minimum: comparative study of the total eclipse drawings in 1706 and 1715

Abstract

We discuss the significant implications of three eye-witness drawings of the total solar eclipse on 1706 May 12 in comparison with two on 1715 May 3, for our understanding of space climate change. These events took place just after what has been termed the “deep Maunder Minimum” but fall within the “extended Maunder Minimum” being in an interval when the sunspot numbers start to recover. Maria Clara Eimmert’s image in 1706 is particularly important because she was both a highly accomplished astronomical observer and an excellent artist: it was thought lost and was only re-discovered in 2012. Being the earliest coronal drawings of observational value yet identified, these drawings corroborate verbal accounts a corona without significant streamers, seen at totality of this and another eclipse event in 1652 during the Maunder Minimum. The graphical evidence implies that the coronal solar magnetic field was not lost but significantly weakened and the lack of coronal structure means there was little discernable open flux (either polar or at lower latitudes) even during the recovery phase of the Maunder Minimum. These observations provide evidence for a different state of oscillation of the solar dynamo and hence behaviour of the Sun in comparison with that during normal solar cycle minima (when a streamer belt between two polar coronal holes is visible) or near normal sunspot maxima (when coronal structure is caused by coronal holes at all latitudes) even to observers without a telescope.

Analyses of a datable solar eclipse record in Maya Classic period monumental inscriptions

“…While naked-eye observations of partial eclipses are challenging even at high magnitudes (e.g., Hayakawa et al (2021) Analyses of the Maya Eclipse Record, Publications of the Astronomical Society of Japan, DOI: 10.1093/pasj/psab088 Chou, 2016), several possibilities have been suggested. First, the Maya could have seen this deep partial eclipse under favourable meteorological conditions, such as a thin cloud cover as a natural filter.…”

“…This contradicts slightly the notion that this stela records the visible total eclipse on 16 July 790 (e.g., Teeple, 1931;Martin and Skidmore, 2012;Love, 2017). In this case, it was probably challenging to Hayakawa et al (2021) Analyses of the Maya Eclipse Record, Publications of the Astronomical Society of Japan, DOI: 10.1093/pasj/psab088 see the solar disk during partial eclipse without appropriate filters (e.g., Chou, 2016). In contrast, following the existing total-eclipse interpretations (Teeple, 1931, p. 115;Love, 2017, p. 3), we need to locate Santa Elena Poco Uinic within the totality path.…”

“…The former is unrealistic, unless otherwise supported by robust reports of contemporary total solar eclipses. Hayakawa et al (2021) Analyses of the Maya Eclipse Record, Publications of the Astronomical Society of Japan, DOI: 10.1093/pasj/psab088 Figure 4: Temporal variation of ΔT and constraints with eclipse records from Stephenson et al (2016) in black bars and from Tanikawa and Sôma (2004) in blue bar, as well as the ΔT range required to realise total eclipse at Santa Elena Poco Uinic on 16 July 790 in red bar.…”

“…Total solar eclipses are spectacular astronomical events and have been recorded in various civilisations for millennia (e.g., Stephenson, 1997;De Jong and Van Soldt, 1989;Pasachoff and Olson, 2014). These events also provide opportunities observations that can aid scientific endeavours such as spectral analyses, calculations of variable coronal dynamics, and measurements of the variable rotation of the Earth (e.g., Sôma and Tanikawa, 2015;Riley et al, 2015;Stephenson et al, 2016;Pasachoff, 2017;Morrison et al, 2019;Hayakawa et al, 2020Hayakawa et al, , 2021. Visibility of total solar eclipses requires an exact apparent coincidence of the solar disk and the lunar disk.…”

“…Hayakawa et al (2021) Analyses of the Maya Eclipse Record, Publications of the Astronomical Society of Japan, DOI: 10.1093/pasj/psab088…”