Structure of Neutron Stars in Massive Scalar-Tensor Gravity

Year: 2020

Type: article

Abstract: We compute families of spherically symmetric neutron-star models in two-derivative scalar-tensor theories of gravity with a massive scalar field. The numerical approach we present allows us to compute the resulting spacetimes out to infinite radius using a relaxation algorithm on a compactified grid. We discuss the structure of the weakly and strongly scalarized branches of neutron-star models thus obtained and their dependence on the linear and quadratic coupling parameters α0, β0 between the scalar and tensor sectors of the theory, as well as the scalar mass μ. For highly negative values of β0, we encounter configurations resembling a “gravitational atom”, consisting of a highly compact baryon star surrounded by a scalar cloud. A stability analysis based on binding-energy calculations suggests that these configurations are unstable and we expect them to migrate to models with radially decreasing baryon density and scalar field strength.

Source: Symmetry

DOI: 10.3390/sym12091384

Authors: Roxana Rosca-Mead, Christopher J. Moore, Ulrich Sperhake, Michalis Agathos, Davide Gerosa

Institutions: University of Cambridge, University of Birmingham, California Institute of Technology

Language: English

Topic: Pulsars and Gravitational Waves Research

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,479

Funders: National Science Foundation, Leverhulme Trust, European Commission, European Cooperation in Science and Technology, Engineering and Physical Sciences Research Council, Science and Technology Facilities Council, European Research Council

OpenAlex ID: W3045728443