Gravitationally Decoupled Strange Star Model beyond the Standard Maximum Mass Limit in Einstein–Gauss–Bonnet Gravity

• Published in: The Astrophysical journal Vol. 925; no. 2; pp. 208 - 225
• Main Authors: Maurya, S. K., Newton Singh, Ksh, Govender, M., Hansraj, Sudan
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01.02.2022; IOP Publishing
• Subjects: Anisotropy; Astrophysics; Compact objects; Decoupling; Equations of state; Flux density; Gravitation; Gravitational effects; Gravity effects; Modelling; Neutron stars; Stars & galaxies; Tensors; Theoretical models
• DOI: 10.3847/1538-4357/ac4255
• ISSN: 0004-637X

The recent theoretical advance known as the minimal geometric deformation (MGD) method has initiated renewed interest in investigating higher-curvature gravitational effects in relativistic astrophysics. In this work, we model a strange star within the context of Einstein–Gauss–Bonnet gravity with the help of the MGD technique. Starting off with the Tolman metric ansatz, together with the MIT bag model equation of state applicable to hadronic matter, anisotropy is introduced via the superposition of the seed source and the decoupled energy-momentum tensor. The solution of the governing systems of equations bifurcates into two distinct models, namely, the mimicking of the θ sector to the seed radial pressure and energy density and a regular fluid model. Each of these models can be interpreted as self-gravitating static, compact objects with the exterior described by the vacuum Boulware–Deser solution. Utilizing observational data for three stellar candidates, namely PSR J1614–2230, PSR J1903+317, and LMC X-4, we subject our solutions to rigorous viability tests based on regularity and stability. We find that the Einstein–Gauss–Bonnet parameter and the decoupling constant compete against each other for ensuring physically realizable stellar structures. The novel feature of the work is the demonstration of stable compact objects with stellar masses in excess of M = 2 M ⊙ without appealing to exotic matter. The analysis contributes new insights and physical consequences concerning the development of ultracompact astrophysical entities.