Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published May 3, 2019 | Submitted
Journal Article Open

The planet nine hypothesis


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 m_g ∼5−10M⊕, residing on a moderately inclined orbit (i_g∼15−25deg) with semi-major axis a_g∼400−800AU and eccentricity between e_g∼0.2−0.5. This paper reviews the observational motivation, dynamical constraints, and prospects for detection of this proposed object known as Planet Nine.

Additional Information

© 2019 Elsevier B.V. Received 5 November 2018, Accepted 30 January 2019, Available online 10 February 2019.

Attached Files

Submitted - 1902.10103.pdf


Files (7.6 MB)
Name Size Download all
7.6 MB Preview Download

Additional details

August 19, 2023
October 20, 2023