Analysis of Hydrogen Lyman-α Observations of the Coma of Comet P/Halley near Perihelion
- 作者：Smyth ; William H. ; Marconi ; M. L. ; Combi ; Michael R.
- 刊名：Icarus
- 出版年：1995
- 期刊代码：90_00191035
- 类别：ph
- 出版时间：January, 1995
- 卷：113
- 期：1
- 页码：119-128
- 文件大小：566 K
摘要
The Pioneer Venus Orbiter Ultraviolet Spectrometer measurements of the Lyman-α intensity of atomic hydrogen excited by solar resonance scattering in the coma of Comet P/Halley acquired from December 28, 1985, to January 6, 1986, and from January 31, 1986, to March 6, 1986, are simulated with the Monte Carlo Particle Trajectory Model corrected for optical depth effects. Spatially detailed comparisons between data and model show excellent agreement and are used to infer that the highest cometary activity may not be at perihelion, but about 2 1/2 weeks before. An improved set of H2O production rates is presented for the period of time that the spectrometer was observing and is found to be consistent with the rates from other types of measurements. The apparent discrepancy between Stewart (1987, Astron. Astrophys. 187, 369-374) in early March and International Ultraviolet Explorer OH derived rates is resolved. The problem with the conversion of 18-cm OH radio brightnesses to H2O production rates is also discussed.