Effects of Fluid Composition on Spherical Flows around Black Holes

TL;DR

This paper investigates how fluid composition affects spherical accretion and wind flows around black holes, revealing that composition significantly influences flow solutions and that Coulomb relaxation times can exceed dynamical times, impacting flow dynamics.

Contribution

It introduces a relativistic EoS for multi-component fluids and demonstrates the importance of composition on flow solutions around black holes.

Findings

Fluid composition alters flow solutions significantly.

Polytropic index depends on temperature and composition.

Coulomb relaxation times can surpass dynamical times.

Abstract

Steady, spherically symmetric, adiabatic accretion and wind flows around non-rotating black holes were studied for fully ionized, multi-component fluids, which are described by a relativistic equation of state (EoS). We showed that the polytropic index depends on the temperature as well as on the composition of fluids, so the composition is important to the solutions of the flows. We demonstrated that fluids with different composition can produce dramatically different solutions, even if they have the same sonic point, or they start with the same specific energy or the same temperature. Then, we pointed that the Coulomb relaxation times can be longer than the dynamical time in the problem considered here, and discussed the implication.