Rings, shells, and arc structures around B[e] supergiants: I. Classical tools of non-linear hydrodynamics

Fuente: arXiv
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Main Authors: Nickeler, Dieter H., Kraus, Michaela
Format: Preprint
Published: 2024
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author Nickeler, Dieter H.
Kraus, Michaela
author_facet Nickeler, Dieter H.
Kraus, Michaela
contents Structures in circumstellar matter reflect both fast processes and quasi-equilibrium states. A geometrical diversity of emitting circumstellar matter is observed around evolved massive stars, in particular around B[e] supergiants. We recapitulate classical analytical tools of linear and non-linear potential theory, such as Cole-Hopf transformations and Grad-Shafranov theory, and develop them further to explain occurrence of the circumstellar matter structures and their dynamics. We use potential theory to formulate the non-linear hydrodynamical equations and test dilatations of the quasi-equilibrium initial conditions. We find that a wide range of flow patterns can basically be generated and the time scales can switch, based on initial conditions, and lead to eruptive processes, reinforcing that the non-linear fluid environment includes both quasi-stationary structures and fast processes like finite-time singularities. Some constraints and imposed symmetries can lead to Keplerian orbits, while other constraints can deliver quasi-Keplerian ones. The threshold is given by a characteristic density at the stellar surface.
format Preprint
id arxiv_https___arxiv_org_abs_2401_08416
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Rings, shells, and arc structures around B[e] supergiants: I. Classical tools of non-linear hydrodynamics
Nickeler, Dieter H.
Kraus, Michaela
Solar and Stellar Astrophysics
Astrophysics of Galaxies
Mathematical Physics
Fluid Dynamics
Space Physics
Structures in circumstellar matter reflect both fast processes and quasi-equilibrium states. A geometrical diversity of emitting circumstellar matter is observed around evolved massive stars, in particular around B[e] supergiants. We recapitulate classical analytical tools of linear and non-linear potential theory, such as Cole-Hopf transformations and Grad-Shafranov theory, and develop them further to explain occurrence of the circumstellar matter structures and their dynamics. We use potential theory to formulate the non-linear hydrodynamical equations and test dilatations of the quasi-equilibrium initial conditions. We find that a wide range of flow patterns can basically be generated and the time scales can switch, based on initial conditions, and lead to eruptive processes, reinforcing that the non-linear fluid environment includes both quasi-stationary structures and fast processes like finite-time singularities. Some constraints and imposed symmetries can lead to Keplerian orbits, while other constraints can deliver quasi-Keplerian ones. The threshold is given by a characteristic density at the stellar surface.
title Rings, shells, and arc structures around B[e] supergiants: I. Classical tools of non-linear hydrodynamics
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
Mathematical Physics
Fluid Dynamics
Space Physics
url https://arxiv.org/abs/2401.08416