Optical analysis of an activity outburst in comet C/1995 O1 (Hale-Bopp) and its connection to an X-ray outburst
Abstract
We present a detailed analysis of an outburst of activity in Comet C/1995 O1 (Hale-Bopp), which coincided in time with an increase in X-ray luminosity of the comet. The outburst produced a cloud of material expanding through the coma and is visible in images obtained with a continuum filter and a CN filter. The evolution of its intensity in both the dust and the CN could be well fitted by a Maxwellian function with two parameters (integrated enhancement and average radius). From this an average radial expansion velocity of 200+/-10 m/s for the dust and 850+/-40 m/s for the CN (phase ~ 19deg) could be derived. We estimate that during the outburst the dust production increased by a factor of > 7 and the CN production by a factor of < 4 relative to the quiescent level. Assuming that the size distribution and albedo of the dust particles released during the outburst remains the same as on ``quiescent'' times and that the variations in CN are representative for all gas production rates in Hale-Bopp, the outburst led to temporarily increased production rates that were about a factor of 2 higher in dust than in gas. The luminosity of the soft X-ray emission observed in Hale-Bopp by the BeppoSAX satellite on September 10-11, 1996, was at least a factor of 3.4 greater than that reported from EUVE observations on September 14-19, 1996. This correlation indicates that the outburst observed in the optical may have triggered the increased X-ray emission on September 10-11, 1996. Based on observations obtained at ESO La Silla within ESO programme No. 57.F-0290
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- September 2000
- Bibcode:
- 2000A&A...361..359S
- Keywords:
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- COMETS: GENERAL;
- COMETS: INDIVIDUAL: C/1995 O1 HALE-BOPP