Stellar structure of quark stars in a modified Starobinsky gravity

Mathew, Arun; Shafeeque, Muhammed; Nandy, Malay K.

doi:10.1140/epjc/s10052-020-8130-4

Cited by 3 publications

(3 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Let us stress that with the purpose of checking the possibility of attaining higher maximum masses for NSs, the present analysis may be extended to incorporate R 2 correction terms in gravitation, what was done, for instance, in [113][114][115]. Note that this incorporation could be a possibility to alleviate the f (R) gravity shortcomings mentioned in the Introduction.…”

Section: Discussionmentioning

confidence: 97%

Neutron stars in f(ℛ,T) gravity using realistic equations of state in the light of massive pulsars and GW170817

Lobato

Lourenço²,

Moraes³

et al. 2020

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

In this work we investigate neutron stars (NS) in f(ℛ,T) gravity for the case R+2λ𝒯, ℛ is the Ricci scalar and 𝒯 the trace of the energy-momentum tensor. The hydrostatic equilibrium equations are solved considering realistic equations of state (EsoS). The NS masses and radii obtained are subject to a joint constrain from massive pulsars and the event GW170817. The parameter λ needs to be negative as in previous NS studies, however we found a minimum value for it. The value should be |λ|≲0.02 and the reason for so small value in comparison with previous ones obtained with simpler EsoS is due to the existence of the NS crust. The pressure in theory of gravity depends on the inverse of the sound velocity vs. Since, vs is low in the crust, |λ| need to be very small. We found that the increment in the star mass is less than 1%, much smaller than previous ones obtained not considering the realistic stellar structure, and the star radius cannot become larger, its changes compared to GR is less than 3.6% in all cases. The finding that using several relativistic and non-relativistic models the variation on the NS mass and radius are almost the same for all the EsoS, manifests that our results are insensitive to the high density part of the EsoS. It confirms that stellar mass and radii changes depend only on crust, where the EoS is essentially the same for all the models. The NS crust effect implying very small values of |λ| does not depend on the theory's function chosen, since for any other one the hydrostatic equilibrium equation would always have the dependence 1/vs. Finally, we highlight that our results indicate that conclusions obtained from NS studies done in modified theories of gravity without using realistic EsoS that describe correctly the NS interior can be unreliable.

show abstract

Section: Discussionmentioning

confidence: 97%

Neutron stars in f(ℛ,T) gravity using realistic equations of state in the light of massive pulsars and GW170817

Lobato

Lourenço²,

Moraes³

et al. 2020

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

show abstract

“…Generally, neutron stars are compact objects with a mass M ∼ 1.4M , a radius R ∼ 12 km, and a central density as high as 5 to 10 times the nuclear equilibrium density n 0 ≈ 0.16 fm −3 of neutrons and protons found in laboratory nuclei (ρ n ≈ 2.3−2.8 × 10 14 g/cm 3 ) [10,11,13]. 2 Neutron stars have been investigated in various modified theories of gravity including, in particular, f (R) gravity [14][15][16][17][18][19][20][21][22], f (R, T ) gravity [23][24][25][26][27], teleparallel gravity [28,29], Einstein-Dilaton-Gauss-Bonnet gravity [30,31], scalar-tensor gravity [32][33][34][35], massive gravity [36], Rastall gravity [37], Eddington-inspired Born-Infeld gravity [38], Hořava-Lifshitz gravity [39] and etc (one can find more references, for example, in the review [40]).…”

Section: Jcap01(2023)005mentioning

confidence: 99%

Anti-de Sitter neutron stars in the theory of gravity with nonminimal derivative coupling

Kashargin

Sushkov

2023

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

We consider neutron star configurations in the scalar-tensor theory of gravity with the coupling between the kinetic term of a scalar field and the Einstein tensor (such the model is a subclass of Horndeski gravity). Neutron stars in this model were studied earlier for the special case with a vanishing “bare” cosmological constant, Λ0 = 0, and a vanishing standard kinetic term, α = 0. This special case is of interest because it admits so-called stealth configuration, i.e. vacuum configuration with nontrivial scalar field and the Schwarzschild metric. However, generally one has Λ0 ≠ 0 and α ≠ 0 and in this case a vacuum configuration is represented as an asymptotically anti-de Sitter (AdS) black hole solution with the nontrivial scalar field. We construct neutron star configurations in this general case and show that resulting diagrams describing the relation between mass and radius of the star essentially differ from those obtained in GR or the particular model with α = Λ0 = 0. Instead, the mass-radius diagrams are similar to those obtained for so-called bare strange stars when a star radius decreases monotonically with decreasing mass. We show also that neutron stars in the theory of gravity with nonminimal derivative coupling are more compact comparing to those in GR or the particular model with α = Λ0 = 0 and suggest a way to estimate possible values of the parameter of nonminimal coupling ℓ. At last, using the Regge-Wheeler method, we discuss briefly the stability of obtained neutron star configurations.

show abstract

“…Generally, neutron stars are compact objects with a mass M ∼ 1.4M ⊙ , a radius R ∼ 12 km, and a central density as high as 5 to 10 times the nuclear equilibrium density n 0 ≈ 0.16 fm −3 of neutrons and protons found in laboratory nuclei (ρ n ≈ 2.3−2.8 × 10 14 g/cm 3 ) [10,11,13]. 2 Neutron stars have been investigated in various modified theories of gravity including, in particular, f (R) gravity [14][15][16][17][18], f (R, T ) gravity [19][20][21][22][23],…”

Section: Introductionmentioning

confidence: 99%

Anti-de Sitter neutron stars in the theory of gravity with nonminimal derivative coupling

Kashargin¹,

Sushkov²

2022

Preprint

View full text Add to dashboard Cite

We consider neutron star configurations in the scalar-tensor theory of gravity with the coupling between the kinetic term of a scalar field and the Einstein tensor (such the model is a subclass of Horndeski gravity). Neutron stars in this model were studied earlier for the special case with a vanishing "bare" cosmological constant, Λ 0 = 0, and a vanishing standard kinetic term, α = 0. This special case is of interest because it admits so-called stealth configuration, i.e. vacuum configuration with nontrivial scalar field and the Schwarzschild metric. However, generally one has Λ 0 = 0 and α = 0 and in this case a vacuum configuration is represented as an asymptotically antide Sitter (AdS) black hole solution with the nontrivial scalar field. We construct neutron star configurations in this general case and show that resulting diagrams describing the relation between mass and radius of the star essentially differ from those obtained in GR or the particular model with α = Λ 0 = 0. Instead, the mass-radius diagrams are similar to those obtained for so-called bare strange stars when a star radius decreases monotonically with decreasing mass. We show also that neutron stars in the theory of gravity with nonminimal derivative coupling are more compact comparing to those in GR or the particular model with α = Λ 0 = 0 and suggest a way to estimate possible values of the parameter of nonminimal coupling ℓ.

show abstract

Stellar structure of quark stars in a modified Starobinsky gravity

Cited by 3 publications

References 46 publications

Neutron stars in f(ℛ,T) gravity using realistic equations of state in the light of massive pulsars and GW170817

Neutron stars in f(ℛ,T) gravity using realistic equations of state in the light of massive pulsars and GW170817

Anti-de Sitter neutron stars in the theory of gravity with nonminimal derivative coupling

Anti-de Sitter neutron stars in the theory of gravity with nonminimal derivative coupling

Contact Info

Product

Resources

About