$R^p$ Attractors Static Neutron Star Phenomenology

TL;DR

This paper explores the effects of $R^p$ attractor theories on neutron star properties by numerically solving the TOV equations and comparing the results with observational constraints, revealing limited viable models.

Contribution

It provides the first detailed analysis of neutron star phenomenology within $R^p$ attractor theories, linking inflationary models to astrophysical observations.

Findings

Few $R^p$ models satisfy neutron star radius constraints

Mass-radius diagrams vary significantly with equations of state

Certain models are ruled out by observational data

Abstract

In this work we study the neutron star phenomenology of $R^p$ attractor theories in the Einstein frame. The Einstein frame $R^p$ attractor theories have the attractor property that they originate from a large class of Jordan frame scalar theories with arbitrary non-minimal coupling. These theories in the Einstein frame provide a viable class of inflationary models, and in this work we investigate their implications on static neutron stars. We numerically solve the Tolman-Oppenheimer-Volkoff equations in the Einstein frame, for three distinct equations of state, and we provide the mass-radius diagrams for several cases of interest of the $R^p$ attractor theories. We confront the results with several timely constraints on the radii of specific mass neutron stars, and as we show, only a few cases corresponding to specific equations of state pass the stringent tests on neutron stars phenomenology.