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Volk_2017_AJ_154_62.pdf
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FInal Published Version
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Univ Arizona, Lunar & Planetary LabIssue Date
2017-07-19
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IOP PUBLISHING LTDCitation
The Curiously Warped Mean Plane of the Kuiper Belt 2017, 154 (2):62 The Astronomical JournalJournal
The Astronomical JournalRights
© 2017. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We measured the mean plane of the Kuiper Belt as a function of semimajor axis. For the classical Kuiper Belt as a whole (the nonresonant objects in the semimajor axis range 42-48 au), we find a mean plane of inclination i(m) = 1 degrees.8(-0 degrees.4)(+0 degrees.7) and longitude of ascending node Omega(m) = 77 degrees(+18 degrees)(-14 degrees) (in the J2000 ecliptic-equinox coordinate system), in accord with theoretical expectations of the secular effects of the known planets. With finer semimajor axis bins, we detect a statistically significant warp in the mean plane near semimajor axes 40-42 au. Linear secular theory predicts a warp near this location due to the nu(18) nodal secular resonance; however, the measured mean plane for the 40.3-42 au semimajor axis bin (just outside the nu(18)) is inclined similar to 13 degrees to the predicted plane, a nearly 3 sigma discrepancy. For the more distant Kuiper Belt objects of semimajor axes in the range 50-80 au, the expected mean plane is close to the invariable plane of the solar system, but the measured mean plane deviates greatly from this: it has inclination i(m) = 9 degrees.1(-3 degrees.8)(+6 degrees.6) and longitude of ascending node Omega(m) = 277 degrees(+18 degrees)(-44 degrees). We estimate this deviation from the expected mean plane to be statistically significant at the similar to 97%-99% confidence level. We discuss several possible explanations for this deviation, including the possibility that a relatively close-in (a less than or similar to 100 au), unseen, small planetary-mass object in the outer solar system is responsible for the warping.ISSN
1538-3881Version
Final published versionSponsors
NASA [NNX14AG93G]; NSF [AST-1312498]Additional Links
http://stacks.iop.org/1538-3881/154/i=2/a=62?key=crossref.4ed2957a680b22c335d13831068d17d8ae974a485f413a2113503eed53cd6c53
10.3847/1538-3881/aa79ff