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Solar Physics

, Volume 126, Issue 1, pp 89–100 | Cite as

Solar differential rotation derived from sunspot observations

  • Maspul Aini Kambry
  • Jun Nishikawa
Article

Abstract

Sunspot drawings obtained at National Astronomical Observatory of Japan during the years 1954–1986 were used to determine the differential rotation of the Sun. From the limited data set of three solar cycles it was found that three factors (the level of cycle activity, the cycle phase, and sunspot type) affect the solar rotation rate. The differential rotation varies from cycle to cycle in such a way that the rotation velocity in the low activity cycle (cycle 20) is higher than in the high-activity cycle (cycle 19). The equatorial rotation rate shows a systematic variation within each cycle. The rate is higher at the beginning of the cycle and decreases subsequently. Although quite small, the variation of solar differential rotation with respect to Zürich sunspot type was found. The H and J types show the slowest rotation among all the sunspot types.

Keywords

Solar Cycle Rotation Rate Systematic Variation Rotation Velocity Cycle Phase 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • Maspul Aini Kambry
    • 1
  • Jun Nishikawa
    • 1
  1. 1.National Astronomical ObservatoryTokyoJapan

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