Detection of Synchronic Bands in the Dust Tail of Comet C/Hale-Bopp 1995 O1

An imaging observation of the dust tail of Comet C/Hale-Bopp 1995O1 was carried out from 1997 March 5 through 9, using a wide-field CCD imaging camera. We detected several striae of degree scale in the dust tail, which could be recognized for the whole observed period. On the basis of a synchrone-syndyne analysis, these striae do not follow any synchrone or syndyne curves. We conclude that these are synchronic bands, which are thought to be made of dust grains originating through secondary processes in the outer coma or in the dust tail. The heliocentric distance of the comet was about 1 AU, which is the greatest distance at which any such synchronic bands have been detected. We report preliminary results of an analysis of these striae, and discuss some of their characteristics, in this paper.