Structure of Compact Stars in R-squared Palatini Gravity

Abstract

We analyse configurations of compact stars in the so-called R-squared gravity in the Palatini formalism. Using a realistic equation of state we show that the mass-radius configurations are lighter than their counterparts in General Relativity. We also obtain the internal profiles, which run in strong correlation with the derivatives of the equation of state, leading to regions where the mass parameter decreases with the radial coordinate in a counter-intuitive way. In order to analyse such correlation, we introduce a parametrisation of the equation of state given by multiple polytropes, which allows us to explicitly control its derivatives. We show that, even in a limiting case where hard phase transitions in matter are allowed, the internal profile of the mass parameter still presents strange features and the calculated M-R configurations also yield NSs lighter than those obtained in General Relativity.

9 pages, 5 figures. Accepted for publication in General Relativity and Gravitation

References in corpus (25)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Shapiro delay measurement of a two solar mass neutron star
• A Massive Pulsar in a Compact Relativistic Binary
• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Disappearing cosmological constant in f(R) gravity
• Modified f(R) gravity consistent with realistic cosmology: from matter dominated epoch to dark energy universe
• Class of viable modified $f(R)$ gravities describing inflation and the onset of accelerated expansion
• Constraints on a phenomenologically parameterized neutron-star equation of state
• Palatini Approach to Modified Gravity: f(R) Theories and Beyond
• Extreme neutron stars from Extended Theories of Gravity
• Nonperturbative models of quark stars in $f(R)$ gravity
• Analytical representations of unified equations of state of neutron-star matter
• Slowly rotating neutron and strange stars in $R^2$ gravity
• Bouncing Cosmologies in Palatini $f(R)$ Gravity
• Surface singularities in Eddington-inspired Born-Infeld gravity
• A no-go theorem for polytropic spheres in Palatini f(R) gravity
• Structure of neutron stars in R-squared gravity
• Rapidly rotating neutron stars in $R$-squared gravity
• On the 1/c Expansion of f(R) Gravity
• Curvature singularities, tidal forces and the viability of Palatini f(R) gravity
• Re-examination of Polytropic Spheres in Palatini f(R) Gravity
• Robust approach to f(R) gravity
• How (Not) to Palatini
• The interior spacetimes of stars in Palatini f(R) gravity
• Stellar configurations in f(R) theories of gravity

Cited by in corpus (1)

• Cooling Process of White Dwarf Stars in Palatini $f(R)$ Gravity