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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A conservative energy-momentum tensor in the f(R,T) gravity and its implications for the phenomenology of neutron stars

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Author(s):
dos Santos, S. I. [1] ; Carvalho, G. A. [1, 2, 3, 4] ; Moraes, P. H. R. S. [1, 5] ; Lenzi, C. H. [1] ; Malheiro, M. [1]
Total Authors: 5
Affiliation:
[1] Inst Tecnol Aeronaut, Dept Fis, BR-12228900 Sao Jose Dos Campos, SP - Brazil
[2] Sapienza Univ Roma, Dipartimento Fis, Ple Aldo Moro 5, I-00185 Rome - Italy
[3] Sapienza Univ Roma, ICRA, Ple Aldo Moro 5, I-00185 Rome - Italy
[4] ICRANet, Piazza Repubbl 10, I-65122 Pescara - Italy
[5] Univ Napoli Federico II, Dipartimento Fis, I-80126 Naples - Italy
Total Affiliations: 5
Document type: Journal article
Source: EUROPEAN PHYSICAL JOURNAL PLUS; v. 134, n. 8 AUG 2019.
Web of Science Citations: 0
Abstract

The solutions for the Tolmann-Oppenheimer-Volkoff (TOV) equation bring valuable information about the macroscopical features of compact astrophysical objects as neutron stars. They are sensitive to both the equation of state considered for nuclear matter and the background gravitational theory. In this work we construct the TOV equation for a conservative version of the f(R, T) gravity. While the non-vanishing of the covariant derivative of the f(R, T) energy-momentum tensor yields, in a cosmological perspective, the prediction of creation of matter throughout the universe evolution, in the analysis of the hydrostatic equilibrium of compact astrophysical objects, this property still lacks a convincing physical explanation. The imposition of del T-mu(mu nu) = 0 demands a particular form for the function h(T) in f(R, T) = R + h(T), which is here derived. Therefore, the choice of a specific equation of state for the stellar matter demands a unique form of h(T), manifesting a strong connection between conserved f(R, T) gravity and the stellar matter constitution. We construct and solve the TOV equation for the general equation of state p = k rho(Gamma), with p being the stellar pressure, k the EoS parameter, rho the energy density and Gamma the adiabatic index. We derive the macroscopical properties of neutron stars (G = 5/3) within this approach and show that their masses are very sensitive to the parameter a that enters in the h(T) function, while their radii are not. These conclusions are in contrast with previous works of compact stars in the non-conservative version of the theory, where the stellar masses do not change considerably but the stellar radii exhibit a large increase, not very consistent with the neutron star phenomenology. (AU)

FAPESP's process: 15/08476-0 - Gravitational waves in f(R,T) theories: polarization states and astrophysical sources
Grantee:Pedro Henrique Ribeiro da Silva Moraes
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 13/26258-4 - Superdense matter in the universe
Grantee:Manuel Máximo Bastos Malheiro de Oliveira
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 18/20689-7 - Gauss-Bonnet Stars
Grantee:Pedro Henrique Ribeiro da Silva Moraes
Support Opportunities: Scholarships abroad - Research Internship - Post-doctor