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An expression for rotational velocity of a test particle around the central mass in the invariant plane is derived. For this, a line element of Schwarzschild de-Sitter space-time is used to study the effect of cosmological constant…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-09 B. Aryal , R. Pandey , N. Baral , U. Khanal , W. Saurer

We make a detailed study of boson star configurations in Jordan--Brans--Dicke theory, studying both equilibrium properties and stability, and considering boson stars existing at different cosmic epochs. We show that boson stars can be…

General Relativity and Quantum Cosmology · Physics 2011-08-11 Diego F Torres , Franz E Schunck , Andrew R Liddle

We study charged boson stars in scalar-tensor (ST) gravitational theories. We analyse the weak field limit of the solutions and analytically show that there is a maximum charge to mass ratio for the bosons above which the weak field…

General Relativity and Quantum Cosmology · Physics 2016-08-25 A. W. Whinnett , Diego F. Torres

We address the existence of globally neutral neutron star configurations in contrast with the traditional ones constructed by imposing local neutrality. The equilibrium equations describing this system are the Einstein-Maxwell equations…

Solar and Stellar Astrophysics · Physics 2009-11-25 Jorge A. Rueda , Remo Ruffini , She-Sheng Xue

Realistic estimations on the elastic properties of neutron star matter are carried out with a large strain ($\varepsilon \lesssim 0.5$) in the framework of relativistic-mean-field model with Thomas-Fermi approximation, where various…

We present a class of exact solutions of Einstein's gravitational field equations describing spherically symmetric and static anisotropic stellar type configurations. The solutions are obtained by assuming a particular form of the…

General Relativity and Quantum Cosmology · Physics 2017-10-04 T. Harko , M. K. Mak

We discuss the stability and construct dynamical configurations describing the gravitational collapse of unstable neutron stars with realistic equations of state compatible with the recent LIGO-Virgo constraints. Unlike other works that…

General Relativity and Quantum Cosmology · Physics 2020-06-17 J. M. Z. Pretel , M. F. A. da Silva

The equation of state inside very compact objects like neutron stars is still largely unkown. Even though a lot progress has been made in recent years to develop the so-called realistic equations of state, a lot of insight can be gained by…

General Relativity and Quantum Cosmology · Physics 2011-06-10 F. M. Araujo , C. B. M. H. Chirenti

We study the static cosmological solutions and their stability at background level in the framework of massive bigravity theory with Friedmann-Robertson-Walker (FRW) metrics. By the modification proposed in the cosmological equations…

General Relativity and Quantum Cosmology · Physics 2017-05-17 M. Mousavi , F. Darabi

Even when we consider Newtonian stars, i.e., stars with surface gravitational redshift, z<< 1, it is well known that, theoretically, it is possible to have stars, supported against self-gravity, almost entirely by radiation pressure.…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Abhas Mitra

The theoretical description of compact structures that share some key features with mass varying particles allows for a simple analysis of equilibrium and stability for massive stellar bodies. We investigate static, spherically symmetric…

General Relativity and Quantum Cosmology · Physics 2010-01-05 Alex E. Bernardini , O. Bertolami

Scalar-tensor~(ST) theories of gravity are natural phenomenological extensions to general relativity. Although these theories are severely constrained both by solar system experiments and by binary pulsar observations, a large set of ST…

General Relativity and Quantum Cosmology · Physics 2016-02-10 Carlos Palenzuela , Steve Liebling

Recent cosmological observations suggest the existence of a positive cosmological constant $\Lambda$ with the magnitude $\Lambda(G\hbar/c^3) \approx 10^{-123}$. This review discusses several aspects of the cosmological constant both from…

High Energy Physics - Theory · Physics 2008-11-26 T. Padmanabhan

We study the internal structure of a static and spherically symmetric neutron star in the framework of an in-medium modified chiral soliton model. The Equations of State describing an infinite and asymmetric nuclear matter are obtained…

Nuclear Theory · Physics 2015-09-30 Ulugbek Yakhshiev

In Horndeski theories containing a scalar coupling with the Gauss-Bonnet (GB) curvature invariant $R_{\rm GB}^2$, we study the existence and linear stability of neutron star (NS) solutions on a static and spherically symmetric background.…

General Relativity and Quantum Cosmology · Physics 2022-09-08 Masato Minamitsuji , Shinji Tsujikawa

The equation of state (EoS) of neutron matter plays a decisive role to understand the neutron star properties and the gravitational waves from neutron star mergers. At sufficient densities, the appearance of hyperons generally softens the…

Nuclear Theory · Physics 2025-02-21 Hui Tong , Serdar Elhatisari , Ulf-G. Meißner

The upper bound on the value of the surface gravity, g_s, for neutron stars with equations of state respecting v_sound <= c, is derived. This bound is inversely proportional to the maximum allowable mass M_max, and it reads g_s <= 1.411 x…

Astrophysics · Physics 2007-05-23 M. Bejger , P. Haensel

We utilize the top-down holographic QCD model, the Witten-Sakai-Sugimoto model, in a hybrid setting with the SLy4, soft chiral EFT and stiff chiral EFT equations of state to describe neutron stars with high precision. In particular, we…

High Energy Physics - Phenomenology · Physics 2024-01-02 Lorenzo Bartolini , Sven Bjarke Gudnason

We study the existence and structure of static and slowly rotating neutron stars (NSs) in a particular truncation of scalar torsion theory with a scalar field $ \phi $ non-minimally coupled to the torsion scalar, and a potential of the form…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Youcef Kehal , Khireddine Nouicer , Hamza Boumaza

We investigate radial oscillations of pure neutron stars and hybrid stars, employing equations of state of nuclear matter from Brueckner-Hartree-Fock theory, and of quark matter from the Dyson-Schwinger quark model, performing a Gibbs…

Nuclear Theory · Physics 2021-05-12 Ting-Ting Sun , Zi-Yue Zheng , Huan Chen , G. Fiorella Burgio , Hans-Josef Schulze