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Observational Constraints on the Lifetime of Cometary H ₂O

Cochran, Anita L.; Schleicher, David G.

We used a carefully selected set of observations of five comets along with a vectorial model and the Haser model to explore the lifetimes against photodissociation of H₂O and OH in cometary comae. The photometric and long-slit CCD data described in this paper were obtained specifically for this project, while the IUE data are archival. …

Water Production Rates in Comet P/Halley from IUE Observations of HI Lyman-β

Feldman, Paul D.; Combi, Michael R.

During the 1985-1986 apparition of Comet P/Halley, the International Ultraviolet Explorer (IUE) satellite observed the comet using both the long-wavelength and short-wavelength spectrographs. The combination of a spherical radiative transfer model and the hybrid gas-dynamic/Monte Carlo model for hydrogen coma, which had been used to analyze H Lyma…