TitleEvidence for a Circumsolar Dust Ring Near Mercury’s Orbit
Publication TypeJournal Article
Year of Publication2018
AuthorsStenborg, G, Stauffer, JR, Howard, RA
JournalThe Astrophysical Journal
Date Published11/2018
Keywords169P&NEAT; 73P&Schwassmann─Wachmann 3; comets: individual: 2P&Encke; methods: data analysis; parker solar probe; Solar Probe Plus; techniques: image processing; zodiacal dust

To test a technique to be used on the white-light imager onboard the recently launched Parker Solar Probe mission, we performed a numerical differentiation of the brightness profiles along the photometric axis of the F-corona models that are derived from STEREO Ahead Sun Earth Connection Heliospheric Investigation observations recorded with the HI-1 instrument between 2007 December and 2014 March. We found a consistent pattern in the derivatives that can be observed from any S/C longitude between about 18° and 23° elongation with a maximum at about 21°. These findings indicate the presence of a circumsolar dust density enhancement that peaks at about 23° elongation. A straightforward integration of the excess signal in the derivative space indicates that the brightness increase over the background F-corona is on the order of 1.5%─2.5%, which implies an excess dust density of about 3%─5% at the center of the ring. This study has also revealed (1) a large-scale azimuthal modulation of the inner boundary of the pattern, which is in clear association with Mercury’s orbit; and (2) a localized modulation of the inner boundary that is attributable to the dust trail of Comet 2P/Encke, which occurs near ecliptic longitudes corresponding to the crossing of Encke’s and Mercury’s orbital paths. Moreover, evidence of dust near the S/C in two restricted ranges of ecliptic longitudes has also been revealed by this technique, which is attributable to the dust trails of (1) comet 73P/Schwassmann─Wachmann 3, and (2) 169P/NEAT.

Short TitleApJ

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