What if Planet 9 is a Primordial Black Hole?
Abstract
We highlight that the anomalous orbits of TransNeptunian Objects (TNOs) and an excess in microlensing events in the 5year OGLE dataset can be simultaneously explained by a new population of astrophysical bodies with mass several times that of Earth ($M_\oplus$). 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.
 Publication:

arXiv eprints
 Pub Date:
 September 2019
 arXiv:
 arXiv:1909.11090
 Bibcode:
 2019arXiv190911090S
 Keywords:

 High Energy Physics  Phenomenology;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 7 pages, 1 exact scale illustration of a 5 Earth mass black hole