Prominence activity and the sunspot cycle

Abstract

The relationship that exists between the distribution and frequencies of prominences at the limb of the sun and the sunspot cycle has been discussed by several workers1. The most outstanding feature is the existence of two distinct zones of prominence activity in each hemisphere. The low-latitude zones extending from the equator to about 50° are always present, although prominence activity in these zones is least at the epoch of sunspot minimum. The high-latitude zones have a different life-history. Prominence activity in these zones drops very suddenly and becomes quite inconspicuous shortly after sunspot maximum. About four years thereafter, a centre of activity develops at about latitude 45°-50°. The activity undergoes a rapid increase and at the same time the prominences extend to higher latitudes. The high-latitude zones become fully developed at the epoch of sunspot maximum.