LAUSR

Abstract The striations in the Type II tail of the comets are called striae. The origin of the striae has been poorly understood. We present a new dynamical model to explain the structure of the striae observed at comets Hale-Bopp (C/1995O1), West (C/1975V1), and Seki-Lines (C/1962C1). Complex particles of absorbent and refractory particles with a radius of less than 1 μm are ejected from the nucleus of the comet and repeatedly decay to form striae with a lifetime of less than about 100 days at 1 AU. They continue to decay further and eventually disappear from sight. The above material science processes are explained by the following dynamical model. The particles ejected from the nucleus of a comet are assumed to be subjected to three forces: solar gravity, solar radiation pressure, and electromagnetic force. As the particle ejected from the nucleus of a comet decreases in size, the radiation pressure increases, decreases, increases and decreases or increases and decreases, forming a stria. The electromagnetic force is treated as an approximate theory and considered as a perturbation. This model is less of a dynamical approximation than previous theories, explains the structure of the striae, and also allows us to predict their luminosity and elucidate the origin of the striae.