Bo-Chen Qian

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

The light curve and images of comet Hale-Bopp (C/1995 OI) 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

Estimating The Dust Particle Size Of Comet Hale–Bopp By Studying The Motion Of The Ejecta On September 10–11, 1996

We report the observation of an outburst of comet Hale–Bopp (C/1995 O1) happened on September 10–11, 1996, carried by the 1.56 m telescope of Shanghai Astronomical Observatory. Two ejecta were found in CCD images during the outburst. According to the positions of ejecta, we discuss the motion of the ejecta considering dust particles are subjected to the gravity and the Solar radiation pressure, and conclude that the mean radii of dust grains in the ejecta were about submicron-sized. So the observed X-ray emission are most likely produced by small size particles scattering the Solar X-ray.

Simulation of shell structures of comet Hale-Bopp

Abstract We present a simulation based on the morphology of inner coma of comet Hale–Bopp(C/1995 O1) which was observed in Shanghai Astronomical Observatory using a 1.56 m telescope in February 1997. The simulation is based on spin stable. Two active regions are suggested by the coma morphology. The dust grains are ejected from the rotating nucleus and subjected to the solar radiation pressure. The trajectories are projected on the sky plane and then they are compared to the observational data. The synthetic images can fit the observation images well. Extended active regions are induced to simulate coma morphology. The results show the spin mode may be a simple one. The precession component, if it exists, may be very small. The RA and Dec. of the pole position of comet Hale–Bopp is 250° and −60° (2000 epoch). Two active sources, latitude of 4° and 34° were simulated according to the morphology.

The light curve of Comet Hale-Bopp in eruption

Abstract In the light curve of Comet Hale-Bopp in 1996 September, we found that a burst took place on Sept. 10–11, when the nuclear magnitude increased by 2.1 mag. We also found two globular ejections near the nucleus in the CCD images taken at the time of the eruption.

Globular ejecta from Comet Hale-Bopp (C/1955 O1)

This paper reports on the eruption of comet Hale-Bopp in September 1996. Two globular ejecta are observed near the nucleus of the comet on Sept. 10 and 11, 1996. We measured the projected velocity to be some 100 m/s. Subsequently the ejecta evolved into a pair of huge jets.

Observation of an explosion in Comet Hale-Bopp

Using the Shanghai Observatory 1.56-m telescope and a Series 200 CCD camera we discovered an explosion on Comet Hale-Bopp between 1996-04-21 and 1996-04-23. On 22, the magnitude was 0.2 mag brighter than on 21, and it was more or less back to the previous brightness on the next day. The half-intensity diameter of the head showed corresponding variations.

A possible plasma jet in Comet Hale-Bopp

Abstract A large jet of Comet Hale-Bopp was observed in the B band on 1996-09-11 with the 1.56-m telescope and a Series 200 CCD camera.

Observations of the collision of Comet SL9 with Jupiter

Abstract Six impacts were observed with the 1.5m telescope and a CCD at Shanghai Observatory Sheshan Station. We give a light curve of the flash on Europa caused by the impact of fragment K12 and four post-collision photographs of Jupiter.

Photoelectric observations of lunar occultations of six binaries in pleiades

Abstract On 1987 December 31, we observed lunar occultations in Pleiades and obtained a series of diffraction curves of stars. After reduction, six stars were found to be double stars, they are SAO 076131, 076140, 076155, 076183, 076236 and 076259. This is the first run of photoelctric occulatation observation with the 1.56 metre telescope.