What if planet 9 has satellites?

TL;DR

This paper explores the possibility that planet 9 could have satellites formed from captured trans-Neptunian objects, offering a new method to detect and study it even if it is a dark object like a primordial black hole.

Contribution

It proposes that planet 9 can capture large TNOs to form satellites, and that tidal heating of these satellites could produce detectable thermal radio flux, providing an indirect detection method.

Findings

High probability of satellite formation around planet 9

Tidal heating can produce observable thermal radio flux

Satellite detection offers a new way to study dark planet 9

Abstract

In the past decade, numerical simulations started to reveal the possible existence of planet 9 in our solar system. The planet 9 scenario can provide an excellent explanation to the clustering in orbital elements for Kuiper Belt objects. However, no optical counterpart has been observed so far to verify the planet 9 scenario. Therefore, some recent studies suggest that planet 9 could be a dark object, such as a primordial black hole. In this article, we show that the probability of capturing large trans-Neptunian objects (TNOs) by planet 9 to form a satellite system in the scattered disk region (between the inner Oort cloud and Kuiper Belt) is large. By adopting a benchmark model of planet 9, we show that the tidal effect can heat up the satellites significantly, which can give sufficient thermal radio flux for observations, even if planet 9 is a dark object. This provides a new indirect way for examining the planet 9 hypothesis and revealing the basic properties of planet 9.