Dynamical instability of polytropic spheres in spacetimes with a cosmological constant

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47813059%3A19630%2F20%3AA0000042" target="_blank" >RIV/47813059:19630/20:A0000042 - isvavai.cz</a>

Výsledek na webu

<a href="https://journals.aps.org/prd/abstract/10.1103/PhysRevD.102.024056" target="_blank" >https://journals.aps.org/prd/abstract/10.1103/PhysRevD.102.024056</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevD.102.024056" target="_blank" >10.1103/PhysRevD.102.024056</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Dynamical instability of polytropic spheres in spacetimes with a cosmological constant

Popis výsledku v původním jazyce

The dynamical instability of relativistic polytropic spheres, embedded in a spacetime with a repulsive cosmological constant, is studied in the framework of general relativity. We apply the methods used in our preceding paper to study the trapping polytropic spheres with Lambda = 0, namely, the critical point method and the infinitesimal and adiabatic radial perturbations method developed by Chandrasekhar. We compute numerically the critical adiabatic index, as a function of the parameter sigma = p_c/(rho_c)^2, for several values of the cosmological parameter lambda giving the ratio of the vacuum energy density to the central energy density of the polytrope. We also determine the critical values for the parameter sigma_cr, for the onset of instability, by using both approaches. We found that for large values of the parameter lambda, the differences between the values of sigma_cr calculated by the critical point method differ from those obtained via the radial perturbations method. Our results, given by both applied methods, indicate that large values of the cosmological parameter lambda have relevant effects on the dynamical stability of the polytropic configurations.

Název v anglickém jazyce

Dynamical instability of polytropic spheres in spacetimes with a cosmological constant

Popis výsledku anglicky

The dynamical instability of relativistic polytropic spheres, embedded in a spacetime with a repulsive cosmological constant, is studied in the framework of general relativity. We apply the methods used in our preceding paper to study the trapping polytropic spheres with Lambda = 0, namely, the critical point method and the infinitesimal and adiabatic radial perturbations method developed by Chandrasekhar. We compute numerically the critical adiabatic index, as a function of the parameter sigma = p_c/(rho_c)^2, for several values of the cosmological parameter lambda giving the ratio of the vacuum energy density to the central energy density of the polytrope. We also determine the critical values for the parameter sigma_cr, for the onset of instability, by using both approaches. We found that for large values of the parameter lambda, the differences between the values of sigma_cr calculated by the critical point method differ from those obtained via the radial perturbations method. Our results, given by both applied methods, indicate that large values of the cosmological parameter lambda have relevant effects on the dynamical stability of the polytropic configurations.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review D

ISSN

1550-7998

e-ISSN

1550-2368

Svazek periodika

102

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

15

Strana od-do

„024056-1“-„024056-15“

Kód UT WoS článku

000549757400007

EID výsledku v databázi Scopus

2-s2.0-85088694255