Science and Exploration

The Planet Nine Hypothesis

By Keith Cowing
Press Release
February 26, 2019
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The Planet Nine Hypothesis
Planet Nine

Over the course of the past two decades, observational surveys have unveiled the intricate orbital structure of the Kuiper Belt, a field of icy bodies orbiting the Sun beyond Neptune.
In addition to a host of readily-predictable orbital behavior, the emerging census of trans-Neptunian objects displays dynamical phenomena that cannot be accounted for by interactions with the known eight-planet solar system alone. Specifically, explanations for the observed physical clustering of orbits with semi-major axes in excess of ∼250AU, the detachment of perihelia of select Kuiper belt objects from Neptune, as well as the dynamical origin of highly inclined/retrograde long-period orbits remain elusive within the context of the classical view of the solar system.

This newly outlined dynamical architecture of the distant solar system points to the existence of a new planet with mass of m9∼5−10M⊕, residing on a moderately inclined orbit (i9∼15−25°) with semi-major axis a9∼400−800AU and eccentricity between e9∼0.2−0.5. This paper reviews the observational motivation, dynamical constraints, and prospects for detection of this proposed object known as Planet Nine.

Konstantin Batygin, Fred C. Adams, Michael E. Brown, Juliette C. Becker
(Submitted on 26 Feb 2019)

Comments: 92 pages, 28 figures, published in Physics Reports
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
DOI: 10.1016/j.physrep.2019.01.009
Cite as: arXiv:1902.10103 [astro-ph.EP] (or arXiv:1902.10103v1 [astro-ph.EP] for this version)
Submission history
From: Konstantin Batygin
[v1] Tue, 26 Feb 2019 18:31:17 UTC (7,069 KB)

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