Skip to main content

Research Repository

Advanced Search

What if Planet 9 is a Primordial Black Hole?

Scholtz, Jakub; Unwin, James

What if Planet 9 is a Primordial Black Hole? Thumbnail


Jakub Scholtz

James Unwin


We highlight that the anomalous orbits of trans-Neptunian objects (TNOs) and an excess in microlensing events in the 5-year Optical Gravitational Lensing Experiment data set can be simultaneously explained by a new population of astrophysical bodies with mass several times that of the Earth (M⊕). We take these objects to be primordial black holes (PBHs) and point out the orbits of TNOs would be altered if one of these PBHs was captured by the Solar System, inline with the Planet 9 hypothesis. Capture of a free floating planet is a leading explanation for the origin of Planet 9, and we show that the probability of capturing a PBH instead is comparable. The observational constraints on a PBH in the outer Solar System significantly differ from the case of a new ninth planet. This scenario could be confirmed through annihilation signals from the dark matter microhalo around the PBH.


Scholtz, J., & Unwin, J. (2020). What if Planet 9 is a Primordial Black Hole?. Physical Review Letters, 125(5), Article 051103.

Journal Article Type Article
Acceptance Date Jun 26, 2020
Online Publication Date Jul 29, 2020
Publication Date 2020-07
Deposit Date Aug 4, 2020
Publicly Available Date Aug 4, 2020
Journal Physical Review Letters
Print ISSN 0031-9007
Electronic ISSN 1079-7114
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 125
Issue 5
Article Number 051103


Published Journal Article (214 Kb)

Publisher Licence URL

Copyright Statement
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

You might also like

Downloadable Citations