Spörer's law

In solar physics, Spörer's law is an empirical law for the variation of heliographic latitudes at which solar active regions form 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 solar cycle, active regions tend to appear around 30° to 45° latitude on the Sun's surface. As the cycle progresses, they appear at lower and lower latitudes, until they average 15° at solar maximum. The average latitude then continues to drift lower, down to about 7° and then while the old sunspot cycle fades, active regions of the new cycle start appearing at high latitudes.^[3]

See also

• Solar variation
• Wolf number
• Joy's law (astronomy)

References

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.