Rings, Shells, and Arc Structures Around B[e] Supergiants. I. Classical Tools of Nonlinear Hydrodynamics

0584794 - ASÚ 2025 RIV GB eng J - Journal Article
Nickeler, Dieter Horst - Kraus, Michaela
Rings, Shells, and Arc Structures Around B[e] Supergiants. I. Classical Tools of Nonlinear Hydrodynamics.
Astrophysical Journal. Roč. 963, č. 2 (2024), č. článku 131. ISSN 0004-637X. E-ISSN 1538-4357
R&D Projects: GA ČR(CZ) GA20-00150S
EU Projects: European Commission(XE) 823734 - POEMS
Institutional support: RVO:67985815
Keywords : hydrodynamics * analytical mathematics * stellar winds
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 4.9, year: 2022
Method of publishing: Open access

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 nonlinear potential theory, such as Cole-Hopf transformation and Grad-Shafranov theory, and develop them further to explain the occurrence of the circumstellar matter structures and their dynamics. We use potential theory to formulate the nonlinear 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 timescales can switch, based on initial conditions, and lead to eruptive processes, reinforcing that the nonlinear 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.
Permanent Link: https://hdl.handle.net/11104/0353512