Stable relativistic polytropic objects with cosmological constant

José D.V. Arbañil; Pedro H.R.S. Moraes

doi:10.1140/epjp/s13360-020-00368-x

Stable relativistic polytropic objects with cosmological constant

José D.V. Arbañil, Pedro H.R.S. Moraes

Grupo de física teórica

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

The effects of the cosmological constant on the static equilibrium configurations and stability against small radial perturbations of relativistic polytropic spheres are investigated. This study numerically solves the hydrostatic equilibrium equation and the radial stability equation, both of which are modified from their standard form to introduce the cosmological constant. For the fluid, we consider a pressure p and an energy density ρ, which are connected through the equation of state p= κδ^Γ with δ= ρ- p/ (Γ- 1) , where κ, Γ and δ represent the polytropic constant, adiabatic index and rest mass density of the fluid, respectively. The dependencies of the mass, radius and eigenfrequency of oscillations on both the cosmological constant and the adiabatic index are analyzed. For ranges of both the central rest mass density δ_c and the adiabatic index Γ, we show that the stars have a larger (lower) mass and radius and a diminished (enhanced) stability when the cosmological constant Λ> 0 (Λ< 0) is increased (decreased). In addition, in a sequence of compact objects with fixed Γ and Λ, the regions constructed by stable and unstable static equilibrium configurations are recognized by the conditions d M/ d δ_c> 0 and d M/ d δ_c< 0 , respectively.

Original language	English
Article number	354
Journal	European Physical Journal Plus
Volume	135
Issue number	4
DOIs	https://doi.org/10.1140/epjp/s13360-020-00368-x
State	Published - 1 Apr 2020

Bibliographical note

Funding Information:
The authors thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), grant 2013 / 26258 - 4 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}2013/26258-4\end{document}. PHRSM would like to thank FAPESP, grant 2015 / 08476 - 0 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}2015/08476-0\end{document}.

Funding Information:
The authors thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), grant . PHRSM would like to thank FAPESP, grant .

Publisher Copyright:
© 2020, Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.

Access to Document

10.1140/epjp/s13360-020-00368-x

Cite this

@article{b1aed6a2a89e4ff6907620e940ca5840,

title = "Stable relativistic polytropic objects with cosmological constant",

abstract = "The effects of the cosmological constant on the static equilibrium configurations and stability against small radial perturbations of relativistic polytropic spheres are investigated. This study numerically solves the hydrostatic equilibrium equation and the radial stability equation, both of which are modified from their standard form to introduce the cosmological constant. For the fluid, we consider a pressure p and an energy density ρ, which are connected through the equation of state p= κδΓ with δ= ρ- p/ (Γ- 1) , where κ, Γ and δ represent the polytropic constant, adiabatic index and rest mass density of the fluid, respectively. The dependencies of the mass, radius and eigenfrequency of oscillations on both the cosmological constant and the adiabatic index are analyzed. For ranges of both the central rest mass density δc and the adiabatic index Γ, we show that the stars have a larger (lower) mass and radius and a diminished (enhanced) stability when the cosmological constant Λ> 0 (Λ< 0) is increased (decreased). In addition, in a sequence of compact objects with fixed Γ and Λ, the regions constructed by stable and unstable static equilibrium configurations are recognized by the conditions d M/ d δc> 0 and d M/ d δc< 0 , respectively.",

author = "Arba{\~n}il, {Jos{\'e} D.V.} and Moraes, {Pedro H.R.S.}",

note = "Publisher Copyright: {\textcopyright} 2020, Societ{\`a} Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.",

year = "2020",

month = apr,

day = "1",

doi = "10.1140/epjp/s13360-020-00368-x",

language = "Ingl{\'e}s",

volume = "135",

journal = "European Physical Journal Plus",

issn = "2190-5444",

publisher = "Springer Science + Business Media",

number = "4",

}

TY - JOUR

T1 - Stable relativistic polytropic objects with cosmological constant

AU - Arbañil, José D.V.

AU - Moraes, Pedro H.R.S.

PY - 2020/4/1

Y1 - 2020/4/1

N2 - The effects of the cosmological constant on the static equilibrium configurations and stability against small radial perturbations of relativistic polytropic spheres are investigated. This study numerically solves the hydrostatic equilibrium equation and the radial stability equation, both of which are modified from their standard form to introduce the cosmological constant. For the fluid, we consider a pressure p and an energy density ρ, which are connected through the equation of state p= κδΓ with δ= ρ- p/ (Γ- 1) , where κ, Γ and δ represent the polytropic constant, adiabatic index and rest mass density of the fluid, respectively. The dependencies of the mass, radius and eigenfrequency of oscillations on both the cosmological constant and the adiabatic index are analyzed. For ranges of both the central rest mass density δc and the adiabatic index Γ, we show that the stars have a larger (lower) mass and radius and a diminished (enhanced) stability when the cosmological constant Λ> 0 (Λ< 0) is increased (decreased). In addition, in a sequence of compact objects with fixed Γ and Λ, the regions constructed by stable and unstable static equilibrium configurations are recognized by the conditions d M/ d δc> 0 and d M/ d δc< 0 , respectively.

AB - The effects of the cosmological constant on the static equilibrium configurations and stability against small radial perturbations of relativistic polytropic spheres are investigated. This study numerically solves the hydrostatic equilibrium equation and the radial stability equation, both of which are modified from their standard form to introduce the cosmological constant. For the fluid, we consider a pressure p and an energy density ρ, which are connected through the equation of state p= κδΓ with δ= ρ- p/ (Γ- 1) , where κ, Γ and δ represent the polytropic constant, adiabatic index and rest mass density of the fluid, respectively. The dependencies of the mass, radius and eigenfrequency of oscillations on both the cosmological constant and the adiabatic index are analyzed. For ranges of both the central rest mass density δc and the adiabatic index Γ, we show that the stars have a larger (lower) mass and radius and a diminished (enhanced) stability when the cosmological constant Λ> 0 (Λ< 0) is increased (decreased). In addition, in a sequence of compact objects with fixed Γ and Λ, the regions constructed by stable and unstable static equilibrium configurations are recognized by the conditions d M/ d δc> 0 and d M/ d δc< 0 , respectively.

UR - http://www.scopus.com/inward/record.url?scp=85083498864&partnerID=8YFLogxK

U2 - 10.1140/epjp/s13360-020-00368-x

DO - 10.1140/epjp/s13360-020-00368-x

M3 - Artículo

AN - SCOPUS:85083498864

SN - 2190-5444

VL - 135

JO - European Physical Journal Plus

JF - European Physical Journal Plus

IS - 4

M1 - 354

ER -

Stable relativistic polytropic objects with cosmological constant

Abstract

Bibliographical note

Access to Document

Other files and links

Fingerprint

Cite this