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@article{41340, author = {Posada Aguirre, Nelson Camilo and Hladík, Jan and Stuchlík, Zdeněk}, article_number = {2}, doi = {http://dx.doi.org/10.1103/PhysRevD.102.024056}, keywords = {polytropic spheres; dynamical instability; cosmological constant}, language = {eng}, issn = {1550-7998}, journal = {Physical Review D}, title = {Dynamical instability of polytropic spheres in spacetimes with a cosmological constant}, url = {https://journals.aps.org/prd/abstract/10.1103/PhysRevD.102.024056}, volume = {102}, year = {2020} }
TY - JOUR ID - 41340 AU - Posada Aguirre, Nelson Camilo - Hladík, Jan - Stuchlík, Zdeněk PY - 2020 TI - Dynamical instability of polytropic spheres in spacetimes with a cosmological constant JF - Physical Review D VL - 102 IS - 2 SP - "024056-1"-"024056-15" EP - "024056-1"-"024056-15" SN - 15507998 KW - polytropic spheres KW - dynamical instability KW - cosmological constant UR - https://journals.aps.org/prd/abstract/10.1103/PhysRevD.102.024056 N2 - 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. ER -
POSADA AGUIRRE, Nelson Camilo, Jan HLADÍK and Zdeněk STUCHLÍK. Dynamical instability of polytropic spheres in spacetimes with a cosmological constant. \textit{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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