These collaborative awards support the group formed to carry out SEPPCoN, a Survey of the Ensemble Physical Properties of Cometary Nuclei. This is a large multi-wavelength project to understand the distribution of sizes, albedos, colors, shapes, and rotations of the current comet population in the Solar System, to investigate how comets have changed in the 4.6 billion years since their formation. This is important, because comets are used to probe the thermo-physical conditions of the proto-planetary disk that led to the formation of the solar system. Although this is a larger question than this survey can answer, SEPPCoN will address aspects related to the make-up of the nuclei themselves, including bulk strength, mass loss, fragmentation, albedos, colors, and axial ratios. Good understanding requires observing a significant sample of the comet population, and this project starts by focusing on Jupiter-family comets (JFCs) with an initial sample of 100 JFC nuclei. This is about 30% of the total known sample and is large enough for statistical rigor. The study uses data from the Spitzer Space Telescope and from ground-based facilities on Mauna Kea, La Silla, La Palma, and Palomar.
The project employs undergraduates for the acquisition, reduction, and presentation of some of the datasets, providing them with a true research experience. Data from this project provide useful context for upper-level undergraduate courses on astronomical techniques. SEPPCoN is an international collaboration among researchers in France, Spain, the United Kingdom, and four U.S. states.
