# Evolution of transonicity in an accretion disc

Source: [Evolution of transonicity in an accretion disc](<https://www.sota2.com/research/paper/68fa29a31e209131ce835e88>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-24T13:01:35.954Z

Authors: Arnab K. Ray, Jayanta K. Bhattacharjee

Published: 2007-03-11T16:46:04.000Z

## Abstract

For inviscid, rotational accretion flows driven by a general pseudo-Newtonian potential on to a Schwarzschild black hole, the only possible fixed points are saddle points and centre-type points. For the specific choice of the Newtonian potential, the flow has only two critical points, of which the outer one is a saddle point while the inner one is a centre-type point. A restrictive upper bound is imposed on the admissible range of values of the angular momentum of sub-Keplerian flows through a saddle point. These flows are very unstable to any deviation from a necessarily precise boundary condition. The difficulties against the physical realisability of a solution passing through the saddle point have been addressed through a temporal evolution of the flow, which gives a non-perturbative mechanism for selecting a transonic solution passing through the saddle point. An equation of motion for a real-time perturbation about the stationary flows reveals a very close correspondence with the metric of an acoustic black hole, which is also an indication of the primacy of transonicity.

## Recorded benchmark results

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/astro-ph/0703251>)

[PDF](<https://arxiv.org/pdf/astro-ph/0703251.pdf>)