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R. L. Comstock (Central Wash. Univ.), N. H. Samarasinha, B. E. A. Mueller (National Optical Astronomy Observatories)
Accurate analysis of cometary observational data requires knowledge of the nuclear rotational state. Determination of the rotational state proves a difficult task for bright comets, since the presence of an obscuring coma dominates nuclear flux variations due to rotation. Even for weakly outgassing comets at large heliocentric distances a low-level coma can make a significant contribution to the derived nuclear magnitudes. The result is an inadequate body of observational data with which to accurately describe the nuclear spin state for many comets. We employ numerical simulations as a method for improving interpretation of spin parameters derived from nuclear lightcurves.
We generate a time series of simulated coma models corresponding to known spin states. The model coma morphology is defined through the input parameters, including parameters defining rotational state. By convolving the simulated coma with a point spread function,then carrying out photometry to extract magnitudes, we generate simulated lightcurves. Comparing periodicities derived from the simulated data with the input parameters, we characterize the observational accuracy for a specific morphology and rotational state. The parameter space of the simulation is sufficiently large to examine a broad, and diverse set of coma morphologies and spin states.
This research is supported by the Kitt Peak National Observatory site program of the Research Experiences for Undergraduates program, funded by the National Science Foundation.
The author(s) of this abstract have provided an email address for comments about the abstract: comstock@televar.com