Looking for extra dimensions in compact stars

5th Compact Stars in the QCD Phase Diagram

Lugones, Germán^1 ; Arbañil, José D.V.^2

Centro de Ciências Naturais e Humanas, Universidade Federal Do ABC, Avenida dos Estados 5001 Santo André, São-Paulo

09210-580, Brazil^1

Departamento de Ciencias, Universidad Privada Del Norte, Av. Alfredo Mendiola Urb. Los Olivos, Lima

6062, Peru^2

关键词: Black hole candidates;    Equilibrium solutions;    Extra dimensions;    Future observations;    General Relativity;    Non-local effect;    Randall-Sundrum;    Stellar structure;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/861/1/012002/pdf
DOI  :  10.1088/1742-6596/861/1/012002

来源: IOP

【 摘 要 】

The properties of spherically symmetric static compact stars are studied in the Randall-Sundrum II type braneworld model assuming that the spacetime outside the star is described by a Schwarzschild metric. The integration of the stellar structure equations employing the so called causal limit equation of state (EoS) shows that the equilibrium solutions can violate the general relativistic causal limit. An analysis of the properties of hadronic and strange quark stars using standard EoSs confirm the same result: there is a branch in the mass-radius diagram that shows the typical behaviour found within the frame of General Relativity and another branch of stars that are supported against collapse by the nonlocal effects of the bulk on the brane. Stars belonging to the new branch can violate the general relativistic causal limit, may have an arbitrarily large mass, and are stable under small radial perturbations. If they exist in Nature, these objects could be hidden among the population of black hole candidates. The future observation of compact stars with masses and radii falling above the causal limit of General Relativity but below the Schwarzschild limit maybe a promising astrophysical evidence for the existence of extra dimensions.