POSADA AGUIRRE, Nelson Camilo, Jan HLADÍK and Zdeněk STUCHLÍK. Dynamical instability of polytropic spheres in spacetimes with a cosmological constant. Physical Review D. 2020, vol. 102, No 2, p. "024056-1"-"024056-15", 15 pp. ISSN 1550-7998. Available from: https://dx.doi.org/10.1103/PhysRevD.102.024056.
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Basic information
Original name Dynamical instability of polytropic spheres in spacetimes with a cosmological constant
Authors POSADA AGUIRRE, Nelson Camilo (170 Colombia, guarantor, belonging to the institution), Jan HLADÍK (203 Czech Republic, belonging to the institution) and Zdeněk STUCHLÍK (203 Czech Republic, belonging to the institution).
Edition Physical Review D, 2020, 1550-7998.
Other information
Original language English
Type of outcome Article in a journal
Field of Study 10308 Astronomy
Country of publisher United States of America
Confidentiality degree is not subject to a state or trade secret
WWW URL
RIV identification code RIV/47813059:19630/20:A0000042
Organization unit Institute of physics in Opava
Doi http://dx.doi.org/10.1103/PhysRevD.102.024056
UT WoS 000549757400007
Keywords in English polytropic spheres; dynamical instability; cosmological constant
Tags FÚ, FÚ2020
Tags International impact, Reviewed
Changed by Changed by: RNDr. Jan Hladík, Ph.D., učo 25379. Changed: 16/3/2021 14:52.
Abstract
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.
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