The Effect of Dust in Small Bodies: A Sample of Jupiter Family Comets

Abstract

There was an unprecedented opportunity to study the inner dust coma environment, where the dust and gas are not entirely decoupled, of Jupiter Family Comets 45P/Honda-Mrkos-Pajdusakov (45P/HMP) from Dec. 26, 2016 - Mar. 15, 2017, 41P/Tuttle-Giacobini-Kresak (41P/TGK) from Feb. 16, 2017 - May 23, 2017, and 46P/Wirtanen from Nov. 10, 2018 - Feb. 13, 2019, in visible wavelengths. During that time period, we also had the opportunity to observe an additional Jupiter Family Comet, 21P/Giacobini-Zinner during its 2018 perihelion passage using narrowband CN photometric imaging, which did not approach Earth as drastically but did provide ample information for a detailed periodicity study. We also had the opportunity to analyze archival data of approximately 180 NEAs taken with the Arecibo Planetary Radar System. We find that 21P/GZ has a period of 10.7 +- 0.2 hours. We measured a lower limit on the CN outflow velocity for the Northern Jet of 1.0 +- 0.1 km s^-1 and for the Southern Jet of 0.8 +- 0.1 km s^-1. In addition, we analyze the morphologies of the jet features and determine that northern pointing jet takes the shape of a corkscrew while the southern pointing is heavily influenced by solar radiation pressure. The azimuthally averaged dust radial profile slope of comet 45P/HMP gradually changes from -1.81+- 0.20 at 5.24 days pre-perihelion to -0.35 +- 0.16 at 74.41 days post perihelion. Contrastingly, the radial profile slope of 46P/Wirtanen stays fairly constant over the observed time period at -1.05 +- 0.05. We also find that 41P/TGK's dust radial profile slope changes from steeper than -1 pre-perihelion to shallower near perihelion, then possibly steepens again. Finally, we find that different asteroid types have vastly different radar albedo, specifically E-type and V-type asteroids.