Re-examination of Polytropic Spheres in Palatini f(R) Gravity

Abstract

We investigate spherically symmetric, static matter configurations with polytropic equation of state for a class of f(R) models in Palatini formalism and show that the surface singularities recently reported in the literature are not physical in the case of Planck scale modified lagrangians. In such cases, they are just an artifact of the idealized equation of state used. In fact, we show that for the models f(R)=R\pmλR^2, with λon the order of the Planck length squared, the presence of a single electron in the Universe would be enough to cure all stellar singularities of this type. From our analysis it also follows that the stellar structure derived from these lagrangians is virtually undistinguishable from that corresponding to General Relativity. For ultraviolet corrected models far from the Planck scale, however, the surface singularities may indeed arise in the region of validity of the polytropic equation of state. This fact can be used to place constraints on the parameters of particular models.

References in corpus (15)

• Limit to General Relativity in f(R) theories of gravity
• The matter power spectrum in f(R) gravity
• f(R) gravity theories in Palatini formalism: cosmological dynamics and observational constraints
• Is loop quantization in cosmology unique?
• A no-go theorem for polytropic spheres in Palatini f(R) gravity
• Violation of the Equivalence Principle in Modified Theories of Gravity
• Spherically symmetric spacetimes in f(R) gravity theories
• Interacting dark energy in $f(R)$ gravity
• The Cosmology of Ricci-Tensor-Squared Gravity in the Palatini Variational Approach
• Hydrogen atom in Palatini theories of gravity
• The viability of theories with matter coupled to the Ricci scalar
• CMB and Matter Power Spectra of Early f(R) Cosmology in Palatini Formalism
• Curvature singularities, tidal forces and the viability of Palatini f(R) gravity
• The interior spacetimes of stars in Palatini f(R) gravity
• Microscopic and Macroscopic Behaviors of Palatini Modified Gravity Theories

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• Role of Tilted Congruence and $f(R)$ Gravity on Regular Compact Objects
• Can higher curvature corrections cure the singularity problem in f(R) gravity?
• Hamiltonian Formulation of Palatini f(R) theories a la Brans-Dicke
• Dynamical Aspects of Generalized Palatini Theories of Gravity
• Junction conditions in Palatini $f(R)$ gravity
• Exact power series solutions of the structure equations of the general relativistic isotropic fluid stars with linear barotropic and polytropic equations of state
• The dynamics of generalized Palatini Theories of Gravity
• Palatini formulation of the conformally invariant $f\left(R,L_m\right)$ gravity theory
• Early evolutionary tracks of low-mass stellar objects in modified gravity
• Strange stars in $f(\mathcal{R})$ gravity Palatini formalism and gravitational wave echoes from them
• Fermi gas and modified gravity
• Cosmology with Hu-Sawicki gravity in Palatini Formalism
• Structure of Compact Stars in R-squared Palatini Gravity
• Metric-affine gravity effects on terrestrial (exo-)planets profiles
• White dwarf stars in modified gravity
• Study of Viable Compact Stellar Structures in Non-Riemannian Geometry
• Birth of baby universes from gravitational collapse in a modified-gravity scenario
• Structure formation in $f(R)$ gravity: A distinguishing probe between the dark energy and modified gravity
• Some Recent Results on Ricci-Based Gravity Theories
• Solar System Tests in Brans-Dicke and Palatini f(R)-theories
• Extended Gravity
• Constraining fundamental parameters in modified gravity using Gaia-DR2 massive white dwarf observation