Spörer's law

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Spörer's law predicts the variation of sunspot latitudes during a solar cycle.[1] It was discovered by the English astronomer Richard Christopher Carrington around 1861.[2] Carrington's work was refined by the German astronomer Gustav Spörer.

At the start of a sunspot cycle, sunspots tend to appear around 30° to 45° latitude on the Sun's surface. As the cycle progresses, sunspots appear at lower and lower latitudes, until they average 15° at solar maximum. The average latitude of sunspots then continues to drift lower, down to about 7° and then while the old sunspot cycle fades, sunspots of the new cycle start appearing at high latitudes.[3]

Sunspot butterfly graph.gif
Butterfly diagram showing paired Spörer's law behavior.

See also[edit]


  1. ^ Hopkins, Jeanne (1980). Glossary of astronomy and astrophysics. Chicago: University of Chicago Press. ISBN 0-226-35171-8.
  2. ^ Carrington, Richard Christopher (1863). Observations of the Spots on the Sun from November 9, 1853, to March 24, 1861, Made at Redhill. London: Williams and Norgate.
  3. ^ Phillips, Kenneth J. H. (1992). Guide to the Sun. Cambridge: Cambridge University Press. ISBN 0-521-39788-X.