Title

A dynamical analysis of the dust tail of Comet C/1995 O1 (Hale-Bopp) at high heliocentric distances

Authors

Authors

E. A. Kramer; Y. R. Fernandez; C. M. Lisse; M. S. P. Kelley;L. M. Woodney

Comments

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Abbreviated Journal Title

Icarus

Keywords

Comets; Comet Hale-Bopp; Comets, dust; SHORT-PERIOD COMETS; INFRARED OBSERVATIONS; NUCLEUS; EVOLUTION; AU; Astronomy & Astrophysics

Abstract

Comet C/1995 O1 (Hale-Bopp) has provided an unprecedented opportunity to observe a bright comet over a wide range of heliocentric distances. We present here Spitzer Space Telescope observations of Hale-Bopp from 2005 to 2008 that show a distinct coma and tail, the presence of which is uncommon given its large heliocentric distance (21.6 AU and 27.2 AU, respectively). The morphology of the dust is compared to dynamical models to understand the activity of the comet. Our analysis shows that the shape of Hale-Bopp's dust tail in these images cannot be explained using the usual Finson-Probstein (solar gravity + solar radiation pressure) dynamical model. Several alternative explanations are explored. The analysis suggests that the most likely cause of the discrepancy is that the dust is being charged by the solar wind, then being affected by the interplanetary magnetic field via the Lorentz force. Though this effect has been explored previously, if correct, this seems to be the first time that the Lorentz force has been required to model a cometary dust tail. The analysis also suggests that Hale-Bopp was actively emitting particles when these images were taken, and the tail characteristics changed between observations. (c) 2014 Elsevier Inc. All rights reserved.

Journal Title

Icarus

Volume

236

Publication Date

1-1-2014

Document Type

Article

Language

English

First Page

136

Last Page

145

WOS Identifier

WOS:000336477400013

ISSN

0019-1035

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