31st Annual Meeting of the DPS, October 1999
Session 17. Comet Comae Posters
Poster Group I, Monday-Wednesday, October 11, 1999, , Kursaal Center

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[17.10] The Water Production Rate of Comet Hale-Bopp as Determined by [O~I] 6300~Å~Measurements

J. P. Morgenthaler, W. Harris, F. Scherb, C. W. Anderson, F. L. Roesler (UW--Madison), R. J. Oliversen (GSFC), N. E. Doane (Raytheon ITSS), W. H. Smyth (AER), M. L. Marconi (FPRI)

The exceptional brightness and long observational window of Comet Hale-Bopp provided a remarkable opportunity to study both the neutral coma and the plasma in the coma and ion tail. Our team of observers from UW--Madison and Goddard Space Fight Center used seven different instruments at Kitt Peak to observe cometary emission from H, OH, O, H2O+, NH2, C, CN, C2, and the continuum. Here we present observations and model analysis for the O(1D) ([O~I]~6300~Å) emission. The data were taken by three telescopes on Kitt Peak: the Wisconsin, Indiana, Yale NRAO (WIYN), Wisconsin H-\alpha Mapper (WHAM), and the NSO McMath-Pierce. The 3.5-meter WIYN telescope recorded up to 96 simultaneous spectra with a Multi-Object Spectrograph (MOS), the WHAM Fabry-Perot spectrometer recorded spectra and narrow-band images over a 1\circ field of view and the 2-inch Fabry-Perot spectrometer at the McMath-Pierce main telescope recorded high resolution (\lambda/\Delta\lambda = 80,000) spectra of the [O~I]~6300~Å~emission with a 6~arcminute field of view. The combination of MOS and Fabry-Perot data covers spatial scales ranging from 2,000~km to 1\times106~km. The high resolution spectra, recorded with a ~180,000~km radius field of view, show evidence of motion in the antisun direction. At distances greater than 300,000~km, we see a tailward asymmetry in the spatial distribution of [O~I]. At 500,000~km, there is an excess of ~2\times106~photons~s-1~cm-2~sr-1 (30~R) in the tailward direction. We use the data away from the tailward asymmetry and the Monte Carlo Particle Trajectory Model (MCPTM) of Combi and Smyth (1988) with recent refinements by Combi, Bos, & Smyth (1993) to estimate the water production rate of the comet in late February and early March of 1997. Preliminary results indicate water production rates of ~1031~molecules/sec. Our observational and data analysis techniques along with possible sources of the asymmetry are discussed.

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The author(s) of this abstract have provided an email address for comments about the abstract: jpmorgen@wisp.physics.wisc.edu

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