000007128 001__ 7128
000007128 005__ 20241021133735.0
000007128 0247_ $$2DOI$$a 10.3847/2041-8213/ad57c9
000007128 037__ $$aSCART-2024-0181
000007128 100__ $$aHayakawa, Hisashi, 
000007128 245__ $$aAnalyses of Johannes Kepler’s Sunspot Drawings in 1607: A Revised Scenario for the Solar Cycles in the Early 17th Century
000007128 260__ $$c2024
000007128 520__ $$aTelescopic sunspot observations began in 1610 and captured subsequent solar cycles. In combination with proxy reconstructions on an annual scale, these data sets indicate a gradual transition between regular solar cycles and the Maunder Minimum. The telescopic sunspot observations missed the beginning of the first telescopic solar cycle (Solar Cycle −13), leaving room for considerable uncertainty as to its temporal evolution. Before these early telescopic observations, however, Kepler made solar observations using camerae obscurae and recorded a sunspot group in three solar drawings in 1607. Here, we make use of Kepler's sunspot drawings and descriptive texts to identify his observational sites and time stamps. We have deprojected his sunspot drawings and compared the reported positions with our calculations of the inclination of the solar equator as seen from these sites at that time. These results locate the reported sunspot group near the solar equator eastward from the central meridian. This contrasts with telescopic sunspot drawings from the 1610s that show sunspot groups in the higher heliographic latitudes. Therefore, what Kepler saw was probably a sunspot group from Solar Cycle −14, rather than one from Solar Cycle −13. These records allow us to place the beginning of Solar Cycle −13 between 1607 and 1610. In comparison with the 14C-based solar-cycle reconstructions, our result supports regular solar-cycle durations around the 1610s, rather than any suggested extreme extensions of the solar-cycle duration(s) around the 1610s.
000007128 594__ $$aSTCE
000007128 700__ $$aMurata, Koji
000007128 700__ $$aTeague, E. Thomas H.
000007128 700__ $$aBechet, Sabrina
000007128 700__ $$aSôma, Mitsuru, 
000007128 773__ $$pThe Astrophysical Journal Letters $$y2024
000007128 8560_ $$fsabrina.bechet@ksb-orb.be
000007128 85642 $$ahttps://iopscience.iop.org/article/10.3847/2041-8213/ad57c9
000007128 905__ $$apublished in
000007128 980__ $$aREFERD