Abstract:
Persistent jet and shell structures from comet Hale-Bopp showing gradual changes in the shapes and orientations with aspect angle and solar illumination geometry indicate long lived active sources. A model to simulate the dust features has been applied to the series of observations from September 1996 to May 1997. Most of the structures can be explained as arising due to ejections from persistent active regions at comet-o-centric latitudes near +65°, +55°, ‑5° to ‑15°, ‑35° and ‑65°. The best fitting pole positions vary between 255° ±10° and 275° ± 10° in right ascension and ‑45° ± 10° to ‑75° ± 10° in declination. Lower limits on the dust and gas production rates at various epochs are presented.
