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Injection of Inner Oort Cloud Objects into the Distant Kuiper Belt by Planet Nine

Batygin, Konstantin and Brown, Michael E. (2021) Injection of Inner Oort Cloud Objects into the Distant Kuiper Belt by Planet Nine. Astrophysical Journal Letters, 910 (2). Art. No. L20. ISSN 2041-8205. doi:10.3847/2041-8213/abee1f.

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The outer solar system exhibits an anomalous pattern of orbital clustering, characterized by an approximate alignment of the apsidal lines and angular momentum vectors of distant, long-term stable Kuiper Belt objects. One explanation for this dynamical confinement is the existence of a yet-undetected planetary-mass object, "Planet Nine (P9)." Previous work has shown that trans-Neptunian objects, that originate within the scattered disk population of the Kuiper Belt, can be corralled into orbital alignment by Planet Nine's gravity over ~Gyr timescales, and characteristic P9 parameters have been derived by matching the properties of a synthetic Kuiper Belt generated within numerical simulations to the available observational data. In this work, we show that an additional dynamical process is in play within the framework of the Planet Nine hypothesis, and demonstrate that P9-induced dynamical evolution facilitates orbital variations within the otherwise dynamically frozen inner Oort cloud. As a result of this evolution, inner Oort cloud bodies can acquire orbits characteristic of the distant scattered disk, implying that if Planet Nine exists, the observed census of long-period trans-Neptunian objects is comprised of a mixture of Oort cloud and Kuiper Belt objects. Our simulations further show that although inward-injected inner Oort cloud objects exhibit P9-driven orbital confinement, the degree of clustering is weaker than that of objects originating within the Kuiper Belt. Cumulatively, our results suggest that a more eccentric Planet Nine is likely necessary to explain the data than previously thought.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Batygin, Konstantin0000-0002-7094-7908
Brown, Michael E.0000-0002-8255-0545
Additional Information:© 2021. The American Astronomical Society. Received 2020 December 30; revised 2021 February 24; accepted 2021 March 11; published 2021 April 6. We are thankful to Alessandro Morbidelli, Darryl Seligman, Juliette Becker, Fred Adams, David Nesvorný, and Eduardo Marturet for insightful discussions. We are additionally grateful to David Nesvorný for sharing his implementation of Galactic tide accelerations. We thank the anonymous referee for providing a thorough and insightful report. K.B. is grateful to Caltech, the David and Lucile Packard Foundation, and the Alfred P. Sloan Foundation for their generous support.
Funding AgencyGrant Number
David and Lucile Packard FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:Trans-Neptunian objects; Planetary dynamics; Oort cloud objects
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Trans-Neptunian objects (1705); Planetary dynamics (2173); Oort cloud objects (1158)
Record Number:CaltechAUTHORS:20210423-164855417
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Official Citation:Konstantin Batygin and Michael E. Brown 2021 ApJL 910 L20
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108830
Deposited By: George Porter
Deposited On:27 Apr 2021 14:47
Last Modified:16 Nov 2021 19:32

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