Neutron Stars in Palatini $R+\alpha R^2$ and $R+\alpha R^2+\beta Q$ Theories

Abstract

We study solutions of the stellar structure equations for spherically symmetric objects in Palatini $f(R)=R+\alpha R^2$ and $f(R,Q)=R+\alpha R^2+\beta Q$ in the mass-radius region associated to neutron stars. We illustrate the potential impact of the $R^2$ and $Q$ terms by studying a range of viable values of $\alpha$ and $\beta$. Similarly, we use different equations of state (SLy, FPS, HS(DD2) and HS(TMA)) as a simple way to account for the equation of state uncertainty. Our results show that for certain combinations of the $\alpha$ and $\beta$ parameters and equation of state, the effect of modifications of general relativity on the properties of stars is sizeable. Therefore, with increasing accuracy in the determination of the equation of state for neutron stars, astrophysical observations may serve as discriminators of modifications of General Relativity.

arXiv comment13 pages, 18 figures. References added. Discussion around Fig. 18 extended. Agrees with published version

References in corpus (63)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• f(R) Theories Of Gravity
• Modified Gravity and Cosmology
• The Confrontation between General Relativity and Experiment
• f(R) theories
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• GW170817: Measurements of Neutron Star Radii and Equation of State
• GW190814: Gravitational Waves from the Coalescence of a 23 M${}_{\odot }$ Black Hole with a 2.6 M${}_{\odot }$ Compact Object
• Relativistic Shapiro delay measurements of an extremely massive millisecond pulsar
• Testing General Relativity with Present and Future Astrophysical Observations
• A unified equation of state of dense matter and neutron star structure
• Properties of the binary neutron star merger GW170817
• Composition and thermodynamics of nuclear matter with light clusters
• Palatini Approach to Modified Gravity: f(R) Theories and Beyond
• Statistical Model for a Complete Supernova Equation of State
• Further stable neutron star models from f(R) gravity
• The Mass-Radius relation for Neutron Stars in $f(R)$ gravity
• Extreme neutron stars from Extended Theories of Gravity
• Ultraviolet properties of f(R)-Gravity
• Stellar structure models in modified theories of gravity: lessons and challenges
• Masses, Deformations and Charge Radii--Nuclear Ground-State Properties in the Relativistic Mean Field Model
• Evidence for a maximum mass cut-off in the neutron star mass distribution and constraints on the equation of state
• Constraints on Perturbative f(R) Gravity via Neutron Stars
• Rotating Stars in Relativity
• Effective Field Theory of Dark Energy: a Review
• Nonperturbative models of quark stars in $f(R)$ gravity
• The realistic models of relativistic stars in f(R) = R + alpha R^2 gravity
• Analytical representations of unified equations of state of neutron-star matter
• Extended Gravity Description for the GW190814 Supermassive Neutron Star
• Hybrid metric-Palatini gravity
• Causal Limit of Neutron Star Maximum Mass in $f(R)$ Gravity in View of GW190814
• Cosmological Tests of Gravity
• Massive gravitational waves from f(R) theories of gravity: Potential detection with LISA
• Surface singularities in Eddington-inspired Born-Infeld gravity
• Asymptotic safety of quantum gravity beyond Ricci scalars
• A no-go theorem for polytropic spheres in Palatini f(R) gravity
• Polarizations of gravitational waves in $f(R)$ gravity
• Palatini inflation in models with an $R^2$ term
• Covariant Effective Action for Loop Quantum Cosmology a la Palatini
• Constraining f(R) gravity in the Palatini formalism
• Reheating in $R^2$ Palatini inflationary models
• Asymptotically safe f(R)-gravity coupled to matter I: the polynomial case
• On the 1/c Expansion of f(R) Gravity
• GW190814: Spin and equation of state of a neutron star companion
• Rescuing Quartic and Natural Inflation in the Palatini Formalism
• Probing the f(R) formalism through gravitational wave polarizations
• Dynamically induced Planck scale and inflation in the Palatini formulation
• Constraining $f(R)$ gravity by the Large Scale Structure
• The interior spacetimes of stars in Palatini f(R) gravity
• Gravitational Wave Polarization Modes in $f(R)$ Theories
• Tracing the high energy theory of gravity: an introduction to Palatini inflation
• Gravitational Waves in $F(R)$ Gravity: Scalar Waves and the Chameleon Mechanism
• An effective action for asymptotically safe gravity
• Quadrupolar gravitational radiation as a test-bed for f(R)-gravity
• Massive relic gravitational waves from f(R) theories of gravity: production and potential detection
• Neutron Stars in Scalar-tensor Gravity with Quartic Order Scalar Potential
• Neutron star solutions in perturbative quadratic gravity
• Structure of Compact Stars in R-squared Palatini Gravity
• Strongest constraint in $f(R)=R+\alpha R^2$ gravity: stellar stability
• Extended Cosmology in Palatini f(R)-theories
• Stellar Structure Equations in Extended Palatini Gravity
• Relativistic stars in Starobinsky gravity with the matched asymptotic expansions method
• Neutron Stars in f(R)-Gravity and Its Extension with a Scalar Axion Field

Cited by in corpus (7)

• Stability criterion for white dwarfs in Palatini $f(R)$ gravity
• Gravitational wave echoes from compact stars in $f(\mathcal{R},T)$ gravity
• Metric-affine effects in crystallization processes of white dwarfs
• The gravitational field of a star in quadratic gravity
• $R^2$-gravity quark stars from perturbative QCD
• Cooling Process of White Dwarf Stars in Palatini $f(R)$ Gravity
• Constraining fundamental parameters in modified gravity using Gaia-DR2 massive white dwarf observation