Microwave observations and modeling of the molecular coma in comets

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This thesis presents observations of comets 73P-C/Schwassmann-Wachmann 3, 17P/Holmes, and 8P/Tuttle at millimeter wavelengths from May 2006 to March 2008, utilizing the Submillimeter and Kitt Peak telescopes of the Arizona Radio Observatory. It also explores in-situ observations of comet 67P/Churyumov-Gerasimenko with the Microwave Instrument for the Rosetta Orbiter (MIRO). The analysis of the first comet suggests an unusually short nucleus rotation period, indicating a potential rotational break-up of the parent body and establishing an upper limit on the nucleus's bulk tensile strength. The second comet's observations detailed the evolution of its molecular environment during a significant outburst, revealing an anisotropic gas cloud resulting from multiple activity sources. The outburst was characterized as a sudden event, with the nucleus returning to expected activity shortly after. The last comet displayed variability in the HCN line profile, attributed to jets from a rotating nucleus, leading to the development of a novel time-dependent anisotropic model of molecular line emission. This model yielded insights into the spin axis orientation and activity distribution of comet Tuttle. Simulations for MIRO observations of comet 67P indicated that water vapor could be detected upon Rosetta's arrival, with optimal observing conditions identified. Overall, this research characterizes three comets, aids in Rosetta's scientific