Observations of a dust tail gap in comet C/2014 Q1 (PanSTARRS)

Abstract

Cometary dust tails display a wide array of structures, most believed to be caused by a variable dust production, size distributions, fragmentation processes, and interactions with the solar wind, e.g. Price et al. (2019). However, not all these structures are fully understood. Here we report the discovery of a curious new dust tail feature, first noted in long period comet C/2014 Q1 (PanSTARRS) (Bolin et al., 2014), where a section of the dust tail was clearly missing. This implies that the comet underwent a dramatic temporary decrease in dust production near perihelion. The gap appeared on 2015 July 14, 8 days after perihelion at 0.318 au, and progressed along the tail, following the expected motion of the dust that should have been present. The gap corresponds to dust ejected between July 5 and July 12, and of β>0.01. Possible explanations for this gap are proposed.