Evidence for a Circumsolar Dust Ring Near Mercury\textquoterights Orbit

Author
Keywords
Abstract
<p>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\textdegree and 23\textdegree elongation with a maximum at about 21\textdegree. These findings indicate the presence of a circumsolar dust density enhancement that peaks at about 23\textdegree 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\textquoterights 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\textquoterights and Mercury\textquoterights 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.</p>
Year of Publication
2018
Journal
The Astrophysical Journal
Volume
868
Number
Number of Pages
74
Date Published
11/2018
URL
http://stacks.iop.org/0004-637X/868/i=1/a=74?key=crossref.819ea43bc5d8ac7ce2e4d9090800ae03
DOI
10.3847/1538-4357/aae6cb