Numerical Solutions and Stability Analysis of White Dwarfs with a Generalized Anisotropic Factor

Orazymbet A. Muratkhan A. Utepova D. Beissen N. Baimbetova G. Toktarbay S.
June 2025 Multidisciplinary Digital Publishing Institute (MDPI)

Galaxies
2025 #13 Issue 3

This study examines the equilibrium structure and stability of white dwarfs, incorporating both isotropic and anisotropic pressure distributions. The Tolman–Oppenheimer–Volkoff (TOV) equation is numerically solved using the Chandrasekhar equation of state (EoS) to analyze the effects of pressure anisotropy. A general anisotropy function is introduced to close and solve the system of differential equations. The results indicate that anisotropy remains negligible at the center and increases toward the stellar surface. Stability is assessed using the speed of sound criterion, (Formula presented.), and the Buchdahl bound, (Formula presented.), confirming that white dwarfs remain within stability limits. We performed a sensitivity analysis to examine how variations in the anisotropy parameter (Formula presented.) and central density affect the mass, radius, and compactness of white dwarfs. Additionally, we calculated the gravitational redshift at the stellar surface and found that it varies with anisotropy, ranging from (Formula presented.) in isotropic cases to (Formula presented.) in highly anisotropic models. These results link anisotropy to potentially observable features. The findings suggest that while anisotropy does not significantly affect the overall equilibrium structure, it may play a role in astrophysical scenarios involving strong magnetic fields, rotational deformations, or accretion processes in binary systems.

compact object , equation of state , stability , white dwarfs

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Institute for Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Faculty of Mathematics, Physics and Informatics, Abai Kazakh National Pedagogical University, Almaty, 050010, Kazakhstan
Department of Science, Abai Kazakh National Pedagogical University, Almaty, 050010, Kazakhstan

Institute for Experimental and Theoretical Physics
Faculty of Mathematics
Department of Science

10 лет помогаем публиковать статьи Международный издатель

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