Long-term Periodicities in North-South Asymmetry of Solar Activity and Alignments of the Giant Planets (2001.05879v1)

Abstract: The existence of ~12-year and ~51-year periodicities in the north-south asymmetry of solar activity is well known. However, the origin of these as well as the well-known relatively short periodicities in the north-south asymmetry is not yet clear. Here we have analyzed the combined daily data of sunspot groups reported in Greenwich Photoheliographic Results (GPR) and Debrecen Photoheligraphic Data (DPD) during the period 1874-2017 and the data of the orbital positions (ecliptic longitudes) of the giant planets in ten-day intervals during the period 1600-2099. Our analysis suggests that ~12-year and ~51-year periodicities in the north-south asymmetry of solar activity are the manifestations of the differences in the strengths of ~11-year and ~51-year periodicities of activity in the northern- and southern-hemispheres. During the period 1874-2017 the Morlet wavelet power spectra of the north-south asymmetry of sunspot-group area and the mean absolute difference of the orbital positions of the giant planets are found to be similar. Particularly, there is a suggestion that the ~12-year and ~51-year periodicities in the north-south asymmetry of sunspot-group area occurred during approximately the same times as the corresponding periodicities in the mean absolute difference of the orbital positions of the giant planets. Therefore, we suggest that there could be influence of some specific configurations of the giant planets in the origin of the ~12-year and ~50-year periodicities of the north-south asymmetry of solar activity.

• The paper presents evidence that the 12-year and 51-year periodicities in solar activity's north-south asymmetry correlate with specific orbital configurations of the giant planets.
• Using sunspot data from 1874-2017 and giant planet positions, the study employed Morlet wavelet analysis to identify these periodic cycles and their temporal alignment.
• These findings suggest that planetary alignments might influence solar dynamics, potentially refining solar dynamo models and improving long-term solar cycle predictions.

Long-term Periodicities in North-South Asymmetry of Solar Activity and Alignments of the Giant Planets

The paper by J. Javaraiah investigates the long-term periodicities in the north-south asymmetry of solar activity, specifically examining the 12-year and 51-year cycles, and explores the potential influence of the giant planets on these periodicities. This research utilizes daily sunspot group data from the Greenwich Photoheliographic Results (GPR) and Debrecen Photoheliographic Data (DPD) for the period 1874 to 2017, alongside orbital positions of the giant planets from 1600 to 2099.

The paper employs Morlet wavelet analysis to identify periodicities within the time series of solar activity asymmetries, with a particular focus on the north-south dichotomy as quantified in both relative and absolute asymmetry measures. The analysis reveals that the known approximately 12-year and approximately 51-year periodicities in solar activity's north-south asymmetry are not random artifacts but rather manifestations of regional cycle strengths differing between the Northern and Southern Hemispheres.

Moreover, the paper draws a correlation between these periodicities and specific orbital configurations of the giant planets—Jupiter, Saturn, Uranus, and Neptune. It posits that certain celestial alignments correlate temporally with the observed solar periodicities. Notably, the Morlet wavelet power spectra of the north-south asymmetry and the average absolute differences of ecliptic longitudes of the giant planets exhibit remarkable similarity, especially regarding the temporal alignment of their 12-year and 51-year cycles.

The implications of these findings extend into the understanding of planetary influence on solar activity—a topic that has seen periodic debate throughout the scientific community. While gravitational and tidal interactions on the Sun from planetary alignments have often been considered negligible, this paper supports the hypothesis that such interactions could indeed influence solar dynamics, particularly in fostering long-period oscillations in solar activity. These findings could potentially refine models of solar dynamo processes, considering external gravitational influences alongside internal magnetic convection.

The results prompt a re-examination of solar activity cycles, particularly how they may be modulated by external celestial forces. These insights could enlighten the development of solar dynamo models and assist in predicting long-term solar behavior. Future investigations may explore more detailed dynamo modeling that includes planetary torque and orbital dynamics. Such studies could deepen the understanding of solar asymmetries and yield better forecasting methods for solar cycles, with applications in understanding space weather phenomena affecting Earth.

In summary, Javaraiah’s research presents compelling evidence that supports the concept of solar-planetary interaction influencing long-term solar periodicities. It opens pathways for further examination into how celestial mechanics might modulate solar activity, offering an enriched perspective on the intricate system connecting our solar system's dynamics to solar magnetic cycles.