Senior Staff Renewal Program
Involving Development of
Inclusive Dates: 03/29/01 - 06/11/01
Background - Time-variable evaporation by solar heating of a still unknown mixture of ices in comet nuclei generates continually escaping gases in the coma of a comet. Solar ultraviolet radiation dissociates and ionizes the gases. They then undergo chemical reactions that change with heliocentric and cometocentric distances. A chemical reaction network linked to solar radiation and gas dynamics is needed to relate the observed species to the icy composition of the nucleus. The ices provide important clues about the origin of the solar system. The objective of the project was to acquire a broader chemical database for the observed species, their parents, and decay products.
Approach - All data were put into a uniform format in a database directly accessible by the user. Data are categorized according to reaction type.
Accomplishments - All data have been placed in a chemical reaction database. SwRI has expanded the list of elements from which molecules can be formed from 8 to 15. The reaction network now contains approximately 240 chemical species related to each other by rate coefficients for over 1,100 reactions. The database also contains species and reactions important for the chemistry of Mars, Jupiter, and Saturn. A start has been made to add references for the sources of the data and quality indicators to identify reliability of the data. Many rate coefficients have been updated with newer rate coefficients. Data are categorized according to reaction types.