Emily Kramer (JPL): "A Survey of Cometary Dust Tails in the WISE Data"


Title: A Survey of Cometary Dust Tails in the WISE Data

Abstract: During the course of the WISE/NEOWISE prime mission, 164 comets were observed, the largest infrared survey of comets by a single instrument, with 108 Short Period Comets (SPCs) and 56 Long Period Comets (LPCs). Eighty-five of these comets displayed significant dust tails in the 12 and 22 um bands (52 SPCs and 33 LPCs), allowing for constraints to be placed on the size and age of the particles. We find that, on average, both LPCs and SPCs have tails that contain significant quantities of large (~mm to cm-sized) particles, and for both populations, the dust is mostly emitted within a few days of each comet's perihelion passage. The finding that both LPC and SPC tails contain appreciable quantities of large dust particles is surprising considering that LPCs and SPCs experience vastly different thermal environments: previous studies have suggested that because LPCs make far fewer close passages to the sun than SPCs, their surfaces are less thermally altered, resulting in an overabundance of small dust particles more recently ejected into their tails relative to larger particles. Our results suggest that despite these environmental differences, the formation of LPCs and SPCs results in dust tails that are more alike than different.