A Possible Source of the X-Rays from Comet Hyakutake

✍ Scribed by T.G. Northrop; C.M. Lisse; M.J. Mumma; M.D. Desch

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 710 KB
• Volume: 127
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.1997.5694

✦ Synopsis

We have made several simple geometric models of the emission rate as a function of position in the radiating region. The purpose was to

The soft X rays from Comet Hyakutake observed by Lisse determine the approximate maximum emission rate per unit volume that et al. (1996, Science 274, 205-209) can reasonably be attributed must be explained. In order to normalize each model we equated the to electron-neutral and electron-dust collisions. The neutrals total emission (i.e., integrated over the volume of the model) to the and dust come from the comet and the electrons from the solar ROSAT measured 4 ϫ 10 15 erg sec Ϫ1 . wind and from photoionization of neutrals. We assume the electron energy spectrum shape to be the same as seen by Vega II. MODELS 2 at Halley's comet, but otherwise use cometary and solar wind parameters observed at Hyakutake.

The models we have tried are either spherically or axisymmetric. The spherically symmetric models are of the form R ϭ R 0 f (r). R is the radiation rate in erg cm Ϫ3 sec Ϫ1 , r is the distance from the radiation