DPS 34th Meeting, October 2002
Session 12. Comets: Comae, Tails, Solar Wind Interaction
Oral, Chair(s): A. Cochran and L.M. Woodney, Tuesday, October 8, 2002, 1:30-3:30pm, Ballroom

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[12.04] Spatially-resolved Spectroscopy of C/2002~C1 (Ikeya-Zhang) with HST

H. A. Weaver (JHU/APL), P. D. Feldman (JHU), M. F. A'Hearn (UMD), C. Arpigny (U. Liège), M. R. Combi (U. Michigan), M. C. Festou (Obs. Midi-Pyrénées), G.-P. Tozzi (Arcetri)

The Hubble Space Telescope (HST) was used to observe C/2002~C1 (Ikeya-Zhang) for 9 orbits during 2002 April~20-23~UT when the comet's heliocentric distance was 0.9~AU and the geocentric distance was 0.4~AU. Spectral images taken with the Space Telescope Imaging Spectrograph (STIS) show cometary emissions from H, O, C, S, CO (4PG and Cameron bands), C\rm 2 (Mulliken bands), CS, S\rm 2, OH, and NH at a spatial resolution better than 0.1~arcsec. The large gas production rate of this comet (Q_{\rm H2O} \sim 2.3 \times 10^{29}), together with the excellent spatial resolution and pointing accuracy of the HST observations, permit a detailed investigation of the spatial brightness profiles of all species in the inner coma. In addition to allowing more accurate determinations of gas production rates, the spatial profiles provide information on the lifetime and source of S\rm 2, the lifetime of the parent of CS, and constraints on the source of CO. Preliminary abundance ratios derived from the STIS spectra are H2O:CO:S_{\rm 2}:CS_{\rm 2} = 100:8:0.0037:0.1.

We gratefully acknowledge financial support from NASA through grant number HST-GO-09496.01 from the STScI, which is operated by AURA under NASA contract NAS5-26555.

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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.