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Search for evidence of a clock related to the solar 154 day complex of periodicities
Sturrock, P. A.; Bai, T.
AA(Stanford Univ., CA), AB(Stanford Univ., CA)
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 397, no. 1, p. 337-346. (ApJ Homepage)
Publication Date:
Solar Physics
NASA/STI Keywords:
Solar Activity, Solar Rotation, Spectrum Analysis, Spherical Harmonics, Sunspots, Nyquist Frequencies, Orbital Mechanics, Oscillators, Power Spectra, Solar Maximum Mission
Bibliographic Code:


Evidence indicates that the 154-day periodicity in solar activity may be part of a complex of periodicities that are approximate multiples of 25.8 d, which suggests that the sun contains a 'clock' with frequency in the range 440-463 nHz. To search for evidence of this clock, the daily Greenwich sunspot areas and daily Zurich sunspot numbers have been Fourier-analyzed. The Zurich data show a strong peak that may clearly be identified with the fundamental frequency, while the Greenwich data show a peak that may be the harmonic of the fundamental frequency. A model is discussed which provides a kinematical interpretation of the sunspot spectrum.

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Database: Astronomy
arXiv e-prints