CAOSP abstracts, Volume: 22, year: 1992


Abstract: The definition is given of recurrent and potentially recurrent sunspot groups, and the principle of constructing OC-diagrams (diagrams of observational conditions of sunspot groups) for potentially recurrent group is described. The conditions are derived under which sunspot groups can be observed as recurrent groups. The frequency distribution of sunspot groups with an actual lifetime of 20 to 40 days is determined by means of OC-diagrams in terms of their observed lifetimes. The non-existence of recurrent sunspot groups with lifetimes of 15 to 25 days, found earlier, is explained as apparent using OC-diagrams. These groups are not observed as a result of the existence of the visibility function.

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