Comets are remnants from the early solar system, and are believed to be the most primitive objects around, representative of the material from which the solar system formed. Studying comets therefore provides a vital link to understanding the origin and evolution of our planetary system. This project will use high-resolution infrared spectroscopy to investigate: (1) the deuterium-to-hydrogen (D/H) ratio in water and methane, its variability within the comet population, and how it compares with D/H ratio measurements elsewhere in the solar system, (2) how the spin temperatures of water and methane vary among the comet population, and (3) the possible classification of comets by their organic volatile composition. The near-infrared contains multiple lines of each species and thus permits the simultaneous search for a number of parent molecules. This research addresses the pressing question of how the degree of deuteration, the spin temperature, and the relative chemical abundances in cometary volatiles, relate to each other and to formation and evolution models for the early solar system. By understanding the diversity of the native volatile abundances, it also addresses observationally the hypothesis of the 'cometary origin' of the terrestrial biosphere.
The research is integrated with secondary school and undergraduate education, including educating teachers and fostering research projects for secondary school students. This will involve both the primary research area and related fundamental fields (physics, chemistry, and biology), and in both metropolitan areas (Washington, DC for PI Dr Boncho Bonev, and Saint Louis, MO for CoPI Dr Erika Gibb). Undergraduate student participants will take part in professional astronomical observing runs and in local and national conferences.
