Geophysics and Tectonics Seminar winter-2016

Ensemble Physical Properties of Comets

With the advent of powerful space-based infrared telescope facilities, we are seeing a surge in the number of cometary nuclei whose thermal emissions are being measured. This work has the potential to provide insight into the ensemble structural and thermophysical properties of comets and, ultimately, the circumstances of their formation and evolution. Moreover, these studies are now happening while the Rosetta spacecraft continues its detailed and lengthy study of comet 67P, giving us excellent context with which to try to understand the wealth of remote observations of other comets. This is important since for the forseeable future there will always be far more comets observed remotely than in-situ, and we must understand what such data are telling us about nuclei and near-nucleus comae so that we are not fooled into misinterpretation. I will review some recent, key results on cometary physical properties and on what we might think of as a “typical” comet. I will also discuss some unanswered questions that should be addressed in the future, and what the observational limitations and opportunities are with regard to them.