scholarly journals Rapidly rotating neutron stars in scalar-tensor theories of gravity

2013 ◽  
Vol 88 (8) ◽  
Author(s):  
Daniela D. Doneva ◽  
Stoytcho S. Yazadjiev ◽  
Nikolaos Stergioulas ◽  
Kostas D. Kokkotas
Keyword(s):  
Neutron Stars ◽  
Theories Of Gravity

scholarly journals Neutron stars in Palatini $$R+\alpha R^2$$ and $$R+\alpha R^2+\beta Q$$ theories

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Georg Herzog ◽  
Hèlios Sanchis-Alepuz
Keyword(s):  
General Relativity ◽  
Equation Of State ◽  
Neutron Stars ◽  
Equations Of State ◽  
Stellar Structure ◽  
Modified Theories Of Gravity ◽  
State Uncertainty ◽  
Structure Equations ◽  
Theories Of Gravity

AbstractWe study solutions of the stellar structure equations for spherically symmetric objects in modified theories of gravity, where the Einstein-Hilbert Lagrangian is replaced by $$f(R)=R+\alpha R^2$$ f ( R ) = R + α R 2 and $$f(R,Q)=R+\alpha R^2+\beta Q$$ f ( R , Q ) = R + α R 2 + β Q , with R being the Ricci scalar curvature, $$Q=R_{\mu \nu }R^{\mu \nu }$$ Q = R μ ν R μ ν and $$R_{\mu \nu }$$ R μ ν the Ricci tensor. We work in the Palatini formalism, where the metric and the connection are assumed to be independent dynamical variables. We focus on stellar solutions in the mass-radius region associated to neutron stars. We illustrate the potential impact of the $$R^2$$ R 2 and Q terms by studying a range of viable values of $$\alpha $$ α and $$\beta $$ β . Similarly, we use different equations of state (SLy, FPS, HS(DD2) and HS(TMA)) as a simple way to account for the equation of state uncertainty. Our results show that for certain combinations of the $$\alpha $$ α and $$\beta $$ β parameters and equation of state, the effect of modifications of general relativity on the properties of stars is sizeable. Therefore, with increasing accuracy in the determination of the equation of state for neutron stars, astrophysical observations may serve as discriminators of modifications of General Relativity.

scholarly journals Extreme neutron stars from Extended Theories of Gravity

2015 ◽  
Vol 2015 (01) ◽  
pp. 001-001 ◽  
Author(s):  
Artyom V. Astashenok ◽  
Salvatore Capozziello ◽  
Sergei D. Odintsov
Keyword(s):  
Neutron Stars ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Extended Theories

scholarly journals Ferromagnetic neutron stars in scalar-tensor theories of gravity

2019 ◽  
Vol 2019 (03) ◽  
pp. 013-013 ◽  
Author(s):  
Zeinab Rezaei ◽  
Habib Yousefi Dezdarani
Keyword(s):  
Neutron Stars ◽  
Theories Of Gravity

scholarly journals Differentially rotating neutron stars in scalar-tensor theories of gravity

2018 ◽  
Vol 98 (10) ◽  
Author(s):  
Daniela D. Doneva ◽  
Stoytcho S. Yazadjiev ◽  
Nikolaos Stergioulas ◽  
Kostas D. Kokkotas
Keyword(s):  
Neutron Stars ◽  
Theories Of Gravity

scholarly journals Oscillation modes of rapidly rotating neutron stars in scalar-tensor theories of gravity

2017 ◽  
Vol 96 (6) ◽  
Author(s):  
Stoytcho S. Yazadjiev ◽  
Daniela D. Doneva ◽  
Kostas D. Kokkotas
Keyword(s):  
Neutron Stars ◽  
Oscillation Modes ◽  
Theories Of Gravity
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