Characterization of the Dust and Sodium Tails of Comet C/2020 F3 (NEOWISE) from Parker Solar Probe and Amateur Observations

Abstract Comet C/2020 F3 (NEOWISE) reached perihelion on 2020 July 3 at 0.29 au and exhibited a highly structured dust tail. Using a simplified Finson–Probstein model, structures such as striae, observed in the tail in images obtained by the Parker Solar Probe spacecraft and amateur observers, are characterized in this work and parameterized in terms of dust ejection dates and dust β values. Other dust tail features are syndynic bands: bright, curved regions of the dust tail that lie within constant values of dust β . This study is the first in-depth analysis of these structures. Analysis revealed that the dust β distribution in the tail was approximately bimodal, corresponding to the two syndynic bands observed in the tail. The region between these bands, bounded by the β = 0.82 ± 0.02 and β = 1.20 ± 0.02 syndynes, appeared to have a reduced dust population, suggesting that dust grains of these β values were produced at a much lower rate. The alignments of the striae in the tail were measured and compared to the interleaved striae seen in C/2006 P1. C/2020 F3 was found to have no interleaved striae, which is possibly due to the timing of the comet’s heliospheric current sheet crossing, not coinciding with, the main period of dust ejection.