aat Acta Astrophys. Tau. Acta Astrophysica Taurica 2712-925X Kiselev Nikolai Nikolaevich, Mosсow, settlement Moskovskii, Tat'yanin Park Str., 12, Moscow, Russia. RU 60 10.34898/aat.vol4.iss2.pp1-5 To the 80th anniversary of V.A. Kotov Sixfold enhancement of solar pulsations: 1974–2018 Kotov Valery Haneychuk Vasilii Crimean Astrophysical Observatory, Nauchny 298409 Crimean Astrophysical Observatory, Nauchny 298409 09 11 2023 4 2 1 5 28 08 2023 Copyright (c) 2026 Kotov V., Haneychuk V. 2026 Valery Kotov, Vasilii Haneychuk The metadata for this submission is licensed under a Creative Commons Attribution 4.0 International License. Copyright and publishing rights for texts published in Acta Astrophysica Taurica is retained by the authors, with first publication rights granted to the journal.Texts are free to use with proper attribution and link to the licensing (Creative Commons Attribution 4.0 International).

Doppler observations of the Sun performed at the Crimean Astrophysical Observatory from 1974 through 2018 show that our star pulsates with the two periods, 9600.606(12) s and 9597.924(13) s. But while the first pulsation was observed during years of the enhanced amplitude only, the second one – over nearly 45 years, with a sixfold amplitude enhancement in 2018 (as compared to the average amplitude of the total 45-year dataset). The characteristic timescale of the amplitude variations, 12(1) years, coincides within the error limits with both the length of the Schwabe 11-year cycle and the sidereal period of Jupiter, 12 years. It also seems puzzling that (a) both periods happened to be near the 9th daily harmonic of the mean solar day, and (b) the beating timescale of these two periods, 398 days, coincides within the error limits with the orbital period of Jupiter, 399 days (synodic). Several evidences for a cosmic nature of the first pulsation are presented, but the true physical cause of both pulsations is not yet understood.

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