Name:	Bauer, James
Email:	bauer@scn.jpl.nasa.gov
Institution:	JPL
Title:	NEOWISE Comets: Nucleus Sizes and Gas Emissions of Comet Populations
Topic:	Discoveries
Abstract:	J. Bauer, A. Mainzer, R. Stevenson, E. Kramer, T. Grav, J. Masiero, R. Cutri, J. Dailey, S. Sonnett, C. Nugent, K. Meech, Y. Fernandez, R. Walker, C. Lisse, A. Waszczak, and E. Wright NEOWISE [1,2] is the planetary-funded mission that utilizes data from the Wide-Field Infrared Survey Explorer (WISE) spacecraft to detect and characterize moving objects. NEOWISE has provided a large statistical sampling of comets in various states of activity, containing a variety of types of comets. This data set provides a unique opportunity to discern the trends in their observable properties and compare the mean properties between classification schemes, and may provide for discerning the underlying populations of comet subtypes. During the prime mission [1], the WISE spacecraft discovered 22 new cometary bodies and observed over 160 comets, yielding the largest sample of comets yet observed at thermal-IR wavelengths. Since the restarted mission [2], these observations have continued, sampling over 60 comets in the first eleven months of the mission, often at multiple heliocentric distances through each comet’s orbit, well on the way to meeting or exceeding the number of comets observed during the prime mission. The prime and restart mission comet samples differ in both the nature of the data and the distribution of detected comets. The two samples offer a diverse range of comet behavior including highly active and inactive bodies from both long period comet (LPC, orbital period > 200 years) and short period comet (SPC, period < 200 years) populations. We have conducted analyses of the physical properties of the NEOWISE-observed comets. In particular, our analysis characterizes the production rates and extent of the CO/CO2 gas species, constrains the quantity and nature of the ejected coma dust for large particles, and provides estimates of the nucleus sizes and albedos. Acknowledgements: This work was supported by NEOWISE, which is a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of NASA. References: [1] Mainzer, A.K., et al. (2011). Preliminary Results from NEOWISE: An Enhancement to the Wide-Field Infrared Survey Explorer for Solar System Science. ApJ 731, 53. [2] Mainzer et al. (2014). Initial Performance of the NEOWISE Reactivation Mission. ApJ 792, 30.