The Lifetime of Sunspot Penumbra Filaments

Abstract

Twenty-seven photographs of a sunspot showing a particularly distinct filamentary structure are analysed in order to obtain an estimate of the lifetime of the penumbral filaments. The photographs have been selected from some 2400 taken over a period of 5 hr. Although the measurements are rendered somewhat uncertain by observational difficulties the results clearly indicate that some filaments remain identifiable for periods of the order of hours.