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[15.03] Discovery of Doubly-Ionized Carbon in the Ion Tail of Comet Kudo-Fujikawa

M. S. Povich, J. C. Raymond (Harvard-Smithsonian Center for Astrophysics), G. H. Jones (Jet Propulsion Laboratory), M. Uzzo, Y.-K. Ko (Harvard-Smithsonian Center for Astrophysics), P. D. Feldman (Johns Hopkins University), P. L. Smith, B. G. Marsden (Harvard-Smithsonian Center for Astrophysics), T. N. Woods (University of Colorado, LASP)

Comet C/2002 X5 (Kudo-Fujikawa) was observed by the Ultraviolet Coronagraph Spectrometer aboard the SOHO spacecraft near its perihelion of 0.19 AU, which occurred on 2003 January 29 at 00:15 UT. Images of the comet were reconstructed from high-resolution spectra obtained at both ends of the 36-hour observing sequence. The H I Ly \alpha 1215.67 Å\ line reveals a quasi-spherical cloud of neutral hydrogen. Also present is a highly variable tail in the C III 977 Å\ line, including a spectacular disconnection event. These observations of C III represent the first detection of any multiply-ionized species in the ion tail of a comet. The water outgassing rate Q_{{\rm H_{2}O}} increased from 5.5\times 10²⁹ s^-1 to 2.65\times 10³⁰ s^-1 over the duration of the observations, while the photometric brightness of the comet increased by ~1 mag. The high abundance of C⁺⁺ and C⁺, \ge 24% relative to water, cannot be explained by photodissociation of CO and is instead attributed to the evaporation and subsequent photoionization of atomic carbon from organic refractory mantles on cometary dust grains.

This work was supported primarily by NASA Grant NAG5-12814. Additional support was provided by NASA Grants NAG5-12865 and NAG5-11420 (UVCS/SOHO), NAG5-9059 (Planetary Atmospheres), and NAG5-12668 (SARA - Laboratory Astrophysics).

The author(s) of this abstract have provided an email address for comments about the abstract: mpovich@cfa.harvard.edu

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.