U017637.pdf (17.03 MB)
Neutral and ionic molecules observed in comet P/Halley.
thesisposted on 2015-11-19, 09:18 authored by A. (Alan) Fitzsimmons
This work is concerned with the study of the coma and gas tail of Hailey's Comet. The thesis begins with a summary of the relevant background material. Theories of origin are discussed, after which the known properties of cometary comae, nuclei and tails are described. Narrow-band photometry of Hailey's Comet both pre- and post-perihelion is documented. The observations of the OH band at 3080A are discussed first, as it is a product of H 2O. Production rates and lifetimes against photodissociation are calculated using both the Haser Model and the Average Random Walk Model. The variation of production rates of CN, C2 and C3 are discussed in the light of current knowledge of Hailey's nucleus. Photodestruction lifetimes of these trace species are found using a Monte-Carlo modelling technique. The analysis of large-scale image of the plasma tail of Hailey is described, resulting in the determination of the solar wind velocity at the comet. The dynamics of the ions in the tail are demonstrated using a simple analytical approximation to the magnetic field structure. Observations of discrete plasma formations within the tail allow the measurement of the internal velocity field, from which an estimate of the tail magnetic field strength is derived.
Date of award1989-01-01
Author affiliationPhysics and Astronomy
Awarding institutionUniversity of Leicester