Distribution Law For Particle Fragmentation Times In A Theory For Striated Tails Of Dust Comets: Application To Comet Hale-Bopp (C/1995 O1)

Sekanina and Farrell's model for the striated dust tails of comets describes the formation of striae as a two-step fragmentation process that is characterized by an ejection time te of parent particles, by their radiation pressure acceleration βp, and by their fragmentation time tf. Of these three, tf is the weakest parameter in that a range oftf offers a set of nearly equivalent solutions. In this context, we comment on Nishioka et al.'s finite-lifetime model, which is a modification of the fragmentation model. We propose a truncated Gaussian function as a first-approximation distribution law for particle fragmentation times. We apply this generalized model to a stria in comet Hale-Bopp detected on March 5–15, 1997 and analyzed by Pittichová et al. in a recent paper. We find that in order to fit the stria's estimated width of ∼150 000 km, the fragmentation times cannot be distributed over a period of more than approximately 2 to 3 days.