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Autor principal: Sánchez-Salcedo, F. J.
Formato: Preprint
Publicado: 2026
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Acceso en línea:https://arxiv.org/abs/2601.16395
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author Sánchez-Salcedo, F. J.
author_facet Sánchez-Salcedo, F. J.
contents We compute the density and velocity profiles along the tail induced by a body of mass $M$, embedded in the midplane of a vertically-stratified media with scaleheight $H$, adopting a one-dimensional model as in the Bondi-Hoyle-Lyttleton problem. In analogy to what occurs in the case of a homogeneous medium, there exist a family of solutions that satisfy the boundary conditions. A shooting method is employed to isolate those solutions that fulfill a specific set of physical and mathematical constraints. The tail is found to be both densest and slowest when the scaleheight $H$ is equal to the gravitational radius $ξ_{0}\equiv GM/v_{0}^{2}$, where $v_{0}$ its relative velocity with respect to the medium. The location of the stagnation point is evaluated as a function of $H$ and $ξ_{0}$, and an empirical fitting formula is provided. While the distance to the stagnation point is maximized when $H\simeq ξ_{0}$, the mass accretion rate attains its maximum value for $H \ll ξ_{0}$ at fixed surface density. When instead the midplane density is held constant and $H$ is varied, the accretion rate hardly changes once $H$ exceeds about $2ξ_{0}$. Additionally, we investigate how both the drag force resulting from mass accretion and the gravitational drag arising from its tail depend on $H/ξ_{0}$. We highlight how the effect of varying the degree of mixing in the tail influences the resulting drag force. Finally, for the particular case of an infinitely thin layer, we provide a simple analytical solution, which may serve as a useful pedagogical reference.
format Preprint
id arxiv_https___arxiv_org_abs_2601_16395
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Bondi-Hoyle-Lyttleton accretion flow in a stratified layer
Sánchez-Salcedo, F. J.
Astrophysics of Galaxies
We compute the density and velocity profiles along the tail induced by a body of mass $M$, embedded in the midplane of a vertically-stratified media with scaleheight $H$, adopting a one-dimensional model as in the Bondi-Hoyle-Lyttleton problem. In analogy to what occurs in the case of a homogeneous medium, there exist a family of solutions that satisfy the boundary conditions. A shooting method is employed to isolate those solutions that fulfill a specific set of physical and mathematical constraints. The tail is found to be both densest and slowest when the scaleheight $H$ is equal to the gravitational radius $ξ_{0}\equiv GM/v_{0}^{2}$, where $v_{0}$ its relative velocity with respect to the medium. The location of the stagnation point is evaluated as a function of $H$ and $ξ_{0}$, and an empirical fitting formula is provided. While the distance to the stagnation point is maximized when $H\simeq ξ_{0}$, the mass accretion rate attains its maximum value for $H \ll ξ_{0}$ at fixed surface density. When instead the midplane density is held constant and $H$ is varied, the accretion rate hardly changes once $H$ exceeds about $2ξ_{0}$. Additionally, we investigate how both the drag force resulting from mass accretion and the gravitational drag arising from its tail depend on $H/ξ_{0}$. We highlight how the effect of varying the degree of mixing in the tail influences the resulting drag force. Finally, for the particular case of an infinitely thin layer, we provide a simple analytical solution, which may serve as a useful pedagogical reference.
title Bondi-Hoyle-Lyttleton accretion flow in a stratified layer
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2601.16395