Hybrid compact stars with finite strange quark mass and dark energy: implications for astrophysical observations

Abstract

In this work, a detailed investigation of compact stars composed of deconfined quark matter with finite strange quark mass ($m_s\ne 0$) admixed with dark energy is presented. The quark sector is modeled using the MIT bag model equation of state, while the dark energy component obeys a linear equation of state, $p^{de}=\omega {\rho }^{de}$ with $\omega$ in the range $-1\le \omega \le -frac13$. The stellar configuration is explored within the Finch-Skea ansatz for the $g_{rr}$ metric potential. A coupling between quark matter and dark energy is introduced through ${\rho }^{de}=\beta {\rho }^Q$, where $\beta$ represents the dark energy coupling parameter. Causality restricts $\beta$ within $0<\beta <-\frac{1}{3\omega }$. The structural features of such compact stars are analysed by varying $\beta$ in this range. Solving the Tolman-Oppenheimer-Volkoff equations yields a maximum mass of $2.012M_{\odot }$ with a radius of about 11 km. For a fixed $\omega$, both mass and radius decrease as $\beta$ increases. The model satisfies causality, energy and stability conditions, ensuring physical acceptability. Finally, the framework is applied to estimate radii of compact star candidates identified as strange quark stars with dark energy, showing good agreement with observational data.

24 pages, 28 figures