Observation of an outburst of comet Hale–Bopp in September 1996

The light curve and images of comet Hale–Bopp (C/1995 O1) in September 1996 are studied. It is found that an outburst happened on 10–11 September 1996. The magnitude of the inner coma region increased by 2.1 and 1.4 mag on these two days, respectively. Two globular ejecta were found near the nucleus of the comet on 10–11 September 1996. By extrapolating backward from the ejecta, it is found that the initial time of the outburst was on 9 September 1996 (9.5±0.2 UT). The physical reason for this outburst is still uncertain. The projected radial velocities of ejecta are 120 and 97 m/s.