Overturning and cracking of stellar objects in modified gravity

Adnan Malik; Attiya Shafaq; Fatemah Mofarreh; M. Farasat Shamir; Wedad Albalawi

doi:10.1140/epjc/s10052-025-13868-w

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2025) 85: 159
https://doi.org/10.1140/epjc/s10052-025-13868-w

Regular Article - Theoretical Physics

Overturning and cracking of stellar objects in modified $f (R, φ)$ $f(R, \varphi )$ gravity

Adnan Malik¹^,2, Attiya Shafaq², Fatemah Mofarreh³^a, M. Farasat Shamir⁴^,5 and Wedad Albalawi³

¹ School of Mathematical Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
² Department of Mathematics, University of Management and Technology, Sialkot Campus, Lahore, Pakistan
³ Mathematical Science Department, Faculty of Science Princess Nourah Bint Abdulrahman University, 11546, Riyadh, Saudi Arabia
⁴ National University of Computer and Emerging Sciences, Lahore Campus, Lahore, Pakistan
⁵ School of Computing and Mathematical Sciences, University of Leicester, Leicester, UK

^a fyalmofarrah@pnu.edu.sa

Received: 25 December 2024
Accepted: 23 January 2025
Published online: 7 February 2025

Abstract

This study extends the concept of cracking to self-gravitating, spherically symmetric compact objects in modified $f (R, φ)$ $f(R, \varphi )$ theory of gravity, where R represents the Ricci scalar, and $φ$ $\varphi$ is the scalar potential. In this regard, we consider spherically symmetric spacetime characterized with an anisotropic matter to detect the instabilities of self-gravitating compact objects via cracking and overturning. Further, we construct the general framework to observe the cracking and overturning points by applying the local density perturbation technique to the configuration governed by barotropic equation of state. The effectiveness of this approach is assessed by analyzing its results on the data of Her X-1, SAX J1808.4-3658, and 4U 1820-30 respectively. It is concluded that cracking points appear in the different interior regions of these three stars. Significantly, this study illustrates the effectiveness of the cracking approach by highlighting the regions sensitive to localized density disruptions, offering valuable insights into the structural behavior of compact stars within a modified gravity framework.

© The Author(s) 2025

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