The Mid-term and Long-term Solar Quasi-periodic Cycles and the Possible Relationship with Planetary Motions

TL;DR

This study identifies multiple solar quasi-periodic cycles across different timescales and explores their potential links to planetary motions, especially highlighting Jupiter's significant influence, to better understand and predict solar activity.

Contribution

It classifies solar cycles into three categories based on their relationship with planetary motions and emphasizes Jupiter's role in influencing these cycles.

Findings

Identified 9 short-period planetary-like cycles related to inner planets and Jupiter.

Found 2 long-period cycles weakly related to outer planets.

Jupiter's motions significantly influence most solar periodic modes.

Abstract

This work investigates the solar quasi-periodic cycles with multi-timescales and the possible relationships with planetary motions. The solar cycles are derived from long-term observations of the relative sunspot number and microwave emission at frequency of 2.80 GHz. A series of solar quasi-periodic cycles with multi-timescales are registered. These cycles can be classified into 3 classes: (1) strong PLC (PLC is defined as the solar cycle with a period very close to the ones of some planetary motions, named as planetary-like cycle) which is related strongly with planetary motions, including 9 periodic modes with relatively short period (P<12 yr), and related to the motions of the inner planets and of Jupiter; (2) weak PLC, which is related weakly to planetary motions, including 2 periodic modes with relatively long period (P>12 yr), and possibly related to the motions of outer planets; (3) non-PLC, which so far has no obvious evidence to show the relationship with any planetary motions. Among planets, Jupiter plays a key role in most periodic modes by its sidereal motion or spring tidal motions with other planets. Among planetary motions, the spring tidal motion of the inner planets and of Jupiter dominates the formation of most PLCs. The relationships between multi-timescale solar periodic modes and the planetary motions will help us to understand the essential natures and prediction of solar activities.