Unequal binary configurations of interacting Kerr-Newman black holes

TL;DR

This paper derives an exact 7-parameter solution describing unequal Kerr-Newman black hole binaries on the axis, including their thermodynamics and interaction forces, with scenarios where the strut disappears during mergers.

Contribution

It provides a new exact analytical solution for unequal Kerr-Newman black hole binaries, including explicit formulas and thermodynamic properties.

Findings

Explicit formulas for horizon half-lengths in terms of physical parameters.

Analysis of thermodynamics and interaction forces.

Scenarios with no strut during black hole mergers.

Abstract

In this paper, binary systems of unequal Kerr-Newman black holes located on the axis and apart by a massless strut are investigated. After adopting a fitting parametrization, the conditions on the axis and the one eliminating the individual magnetic charges are solved exactly with the aim to obtain a 7-parametric asymptotically flat exact solution. It is also deduced explicit analytical formulas for each half-length horizon ${\sigma}_{i}$, $i = 1,2$, in terms of arbitrary physical Komar parameters: mass $M_{i}$, electric charge $Q_{i}$, angular momentum $J_{i}$, and a coordinate distance $R$. All the thermodynamical properties for the black holes as well as the interaction force related to the strut are also given in a concise way. Our analysis permits us to derive in detail the physical limits of the solution and introduce some scenarios where the strut is absent during the merger process.