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An ungravity-inspired model is employed to examine the astrophysical parameters of white dwarf stars (WDs) using polytropic and degenerate gas approaches. Based on the observed properties such as mass, radius, and luminosity of selected…

Solar and Stellar Astrophysics · Physics 2016-06-06 Orfeu Bertolami , Hodjat Mariji

The Einstein-Maxwell (or Einstein) system of field equations plays a substantial role in the modeling of compact stars. Although due to its non-linearity getting an exact solution for the system of field equations is a difficult task, the…

General Relativity and Quantum Cosmology · Physics 2022-01-26 Jitendra Kumar , Puja Bharti

A special form of the isotropic metric in cylindrical coordinates is used to construct what may be interpreted as the General Relativistic versions of some wellknown potential-density pairs used in Newtonian gravity to model…

Astrophysics · Physics 2009-11-13 D. Vogt , P. S. Letelier

Certain physical quantities that characterize neutron stars and quark stars (e.g. their mass, spin angular momentum and quadrupole moment) are interrelated in a way that is approximately insensitive to their internal structure. Such…

General Relativity and Quantum Cosmology · Physics 2024-07-23 Kent Yagi , Nicolas Yunes

A simple result for the pressure of a hard sphere fluid that was developed many years ago by Rennert is extended in a straightforward manner by adding the terms that are of the same form as the Rennert's formula. The resulting expression is…

Soft Condensed Matter · Physics 2013-12-13 D. Henderson

We find two new classes of exact solutions to the Einstein-Maxwell system of equations. The matter distribution satisfies a linear equation of state consistent with quark matter. The field equations are integrated by specifying forms for…

General Relativity and Quantum Cosmology · Physics 2015-06-23 Jefta M. Sunzu , Sunil D. Maharaj , Subharthi Ray

We study the general formalism of polytropes in relativistic regime with generalized polytropic equations of state in the vicinity of cylindrical symmetry. We take charged anisotropic fluid distribution of matter with conformally flat…

General Physics · Physics 2016-10-12 M. Azam , S. A. Mardan , I. Noureen , M. A. Rehman

In this paper, we studied the behavior of relativistic objects with anisotropic matter distribution considering Tolman IV form for the gravitational potential Z. The equation of state presents a quadratic relation between the energy density…

General Physics · Physics 2015-03-29 Manuel Malaver

Modified dispersion relations from effective field theory are shown to alter the Chandrasekhar mass limit. At exceptionally high densities, the modifications affect the pressure of a degenerate electron gas and can increase or decrease the…

Astrophysics · Physics 2010-06-22 Michael Gregg , Seth A. Major

Phenomenological calculations of the properties of dense matter, such as relativistic mean-field theories, represent a pathway to predicting the microscopic and macroscopic properties of neutron stars. However, such theories do not…

Nuclear Theory · Physics 2025-11-03 Isaac Legred , Liam Brodie , Alexander Haber , Reed Essick , Katerina Chatziioannou

In this article we have extended the original work of Chandrasekhar on the structure of white dwarfs to the two-dimensional case. Although such two-dimensional stellar objects are hypothetical in nature, we strongly believe that the work…

Solar and Stellar Astrophysics · Physics 2015-02-20 Sanchari De , Somenath Chakrabarty

In this article, we investigate the properties of neutron stars within the braneworld model, employing six distinct piece-wise polytropic equation of states. These equation of states satisfy observational constraints put by GW170817 event…

General Relativity and Quantum Cosmology · Physics 2025-01-22 Masum Murshid , Nilofar Rahman , Mehedi Kalam

In this contribution, we briefly present the equation-of-state modelling for application to neutron stars and discuss current constraints coming from nuclear physics theory and experiments. To assess the impact of model uncertainties, we…

High Energy Astrophysical Phenomena · Physics 2023-11-14 A. F. Fantina , F. Gulminelli

In this work, we have investigated anisotropic neutron stars in the framework of Rastall-Rainbow gravity. All our calculations were computed using the IU-FSU realistic equation of state (EoS), in which was considered two cases: standard…

High Energy Astrophysical Phenomena · Physics 2019-11-11 Clésio E. Mota , Luis C. N. Santos , Franciele M. da Silva , Cesar V. Flores , Tiago J. N. da Silva , Débora P. Menezes

We present a spherically symmetric solution of the general relativistic field equations in isotropic coordinates for anisotropic neutral fluid, compatible with a super dense star modeling by considering a specific choice of anisotropy…

General Relativity and Quantum Cosmology · Physics 2014-10-23 Neeraj Pant , Narendra Pradhan , Manuel Malaver

The equation of state of neutron matter is affected by the presence of a magnetic field due to the intrinsic magnetic moment of the neutron. Here we study the equilibrium configuration of this system for a wide range of densities,…

Nuclear Theory · Physics 2014-10-15 R. Aguirre , E. Bauer , I. Vidaña

New exact interior solutions to the Einstein field equations for anisotropic spheres are found. We utilise a procedure that necessitates a choice for the energy density and the radial pressure. This class contains the constant density model…

General Relativity and Quantum Cosmology · Physics 2009-11-11 M. Chaisi , S. D. Maharaj

In this study we explore the astrophysical implications of pressure anisotropy on the physical characteristics of millisecond pulsars within the framework of $f(Q)$ gravity, {in particular $f(Q)=-\alpha\, Q - \beta$, where $\alpha$ and…

General Relativity and Quantum Cosmology · Physics 2024-10-08 S. K. Maurya , Ksh. Newton Singh , G. Mustafa , M. Govender , Abdelghani Errehymy , Abdul Aziz

Set of neutron star observational results is used to test some selected equations of state of dense nuclear matter. The first observational result comes from the mass--baryon number relation for pulsar B of the double pulsar system J…

Solar and Stellar Astrophysics · Physics 2010-07-21 Martin Urbanec , Emil Betak , Zdenek Stuchlik

Recently, it has been shown by S.~M. de Carvalho et al. (2014) that the deviations between the degenerate case and observations were already evident for 0.7-0.8 M$_{\odot}$ white dwarfs. Such deviations were related to the neglected effects…

Solar and Stellar Astrophysics · Physics 2016-04-13 Kuantay Boshkayev , Jorge A. Rueda , Bakytzhan Zhami , Zhanerke Kalymova , Galymdin Balgymbekov