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Related papers: Conformable Fractional Isothermal Gas Spheres

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Lane Emden differential equation of the polytropic gas sphere could be used to construct simple models of stellar structures, star clusters and many configurations in astrophysics. This differential equation suffers from the singularity at…

Solar and Stellar Astrophysics · Physics 2020-03-25 E. A. -B. Abd-Elsalam , Mohamed I. Nouh

The isothermal gas sphere is a particular type of Lane-Emden equation and is used widely to model many problems in astrophysics like stars, star clusters, and the formation of galaxies. In this paper, we present a computational scheme to…

Astrophysics of Galaxies · Physics 2021-03-31 Yosry A. Azzam , Emad A. -B. Abdel-Salam , Mohamed I. Nouh

In this paper, we introduce a novel analytical solution to Tolman-Oppenheimer-Volkoff (TOV) equation, which is ultimately a hydrostatic equilibrium equation derived from the general relativity in the framework of relativistic isothermal…

General Relativity and Quantum Cosmology · Physics 2017-05-01 A. S. Saad , M. I. Nouh , A. A. Shaker , T. M. Kamel

We investigate the effects of relativity on the gravitational instability of finite isothermal gaseous spheres. In the first part of the paper, we treat the gravitational field within the framework of Newtonian mechanics but we use a…

Astrophysics · Physics 2009-11-07 Pierre-Henri Chavanis

Lane-Emden equation could be used to model stellar interiors, star clusters and many configurations in astrophysics. Unfortunately, there is an exact solution only for the polytropic index and . In the present paper, a series solution for…

Solar and Stellar Astrophysics · Physics 2020-03-25 Mohamed I. Nouh , Emad A-B. Abdel-Salam

We complete our previous investigation concerning the structure and the stability of "isothermal" spheres in general relativity. This concerns objects that are described by a linear equation of state $P=q\epsilon$ so that the pressure is…

Astrophysics · Physics 2009-11-13 Pierre-Henri Chavanis

A theory for the structure of isothermal, self-gravitating gas spheres in pressure equilibrium in a softened gravitational field is developed. The one parameter spline softening proposed by Hernquist & Katz (1989) is used. We show that the…

Astrophysics · Physics 2009-10-28 Jesper Sommer-Larsen , Henrik Vedel , Uffe Hellsten

Instead of conformal to flat spacetime, we take the metric conformal to a spacetime which can be thought of as ``minimally'' curved in the sense that free particles experience no gravitational force yet it has non-zero curvature. The base…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Naresh Dadhich

We construct a toy model for isothermal spheres in Horava gravity, which includes Einstein's gravity if a parameter is appropriately chosen. The equations for the isothermal spheres are derived from the partition function of the gravitating…

General Relativity and Quantum Cosmology · Physics 2021-03-31 Nahomi Kan , Kiyoshi Shiraishi

We analytically study isothermal spheres in the light of nonextensive statistical mechanics. The equations for the isothermal spheres are derived from the grand partition function of the gravitating particle system in the Tsallis…

General Relativity and Quantum Cosmology · Physics 2025-09-24 Nahomi Kan , Takuya Maki , Kiyoshi Shiraishi

We present a general solution of the Einstein gravitational field equations for the static spherically symmetric gravitational interior spacetime of an isotropic fluid sphere. The solution is obtained by transforming the pressure isotropy…

General Relativity and Quantum Cosmology · Physics 2015-06-17 M. K. Mak , T. Harko

We present a derivation of the mechanics of isothermal gas spheres directly from the Vlasov--Poisson equation. By extremising the Boltzmann entropy, we obtain the Maxwell--Boltzmann distribution for a self-gravitating isothermal Newtonian…

Astrophysics of Galaxies · Physics 2025-11-13 Steven D Miller

We investigate insterstellar gas spheres by determining the metric functions, the material distribution, and the features of particle orbits in terms of stability and geodesics. An exact solution of the Einstein's equations for interstellar…

General Relativity and Quantum Cosmology · Physics 2017-08-21 Dániel Barta

We present a new 3D SPH code which solves the general relativistic field + hydrodynamics equations in the conformally flat approximation. Several test cases are considered to test different aspects of the code. We finally apply then the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Roland Oechslin , Stephan Rosswog , Friederich-Karl Thielemann

A highly accurate, multi-domain spectral code is used in order to construct sequences of general relativistic, differentially rotating neutron stars in axisymmetry and stationarity. For bodies with a spheroidal topology and a homogeneous or…

General Relativity and Quantum Cosmology · Physics 2016-06-01 Marcus Ansorg , Dorota Gondek-Rosińska , Loïc Villain

In the process of protostar formation, astrophysical gas clouds undergo thermodynamically irreversible processes and emit heat and radiation to their surroundings. Due the emission of this energy one can envision an idealized situation in…

General Relativity and Quantum Cosmology · Physics 2016-11-22 Mayer Humi , John Roumas

Fractional calculus is an effective tool in incorporating the effects of non-locality and memory into physical models. In this regard, successful applications exist rang- ing from signal processing to anomalous diffusion and quantum…

General Physics · Physics 2014-08-26 S. S. Bayin , J. P. Krisch

A novel large volume spherical proportional counter, recently developed, is used for neutron measurements. Gas mixtures of $N_{2}$ with $C_{2}H_{6}$ and pure $N_{2}$ are studied for thermal and fast neutron detection, providing a new way…

We have reexamined the similarity solution for a self-gravitating isothermal gas sphere and examined implication to star formation in a turbulent cloud. When parameters are adequately chosen, the similarity solution expresses an accreting…

Astrophysics · Physics 2009-11-13 Tomoyuki Hanawa , Akihito Soeda

Many stellar configurations, including white dwarfs, neutron stars, black holes, supermassive stars, and star clusters, rely on relativistic effects. The Tolman-Oppenheimer-Volkoff (TOV) equation of the polytropic gas sphere is ultimately a…

General Relativity and Quantum Cosmology · Physics 2024-05-31 Mohamed S. Aboueisha , Mohamed I. Nouh , Emad A-B. Abdel-Salam. Tarek M. Kamel , Mohamed M. Beheary , Kamel A. K. Gadallah
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