Impact of Charge on the Stability of Pulsar SAX J1748.9-2021 in Modified Symmetric Teleparallel Gravity

Abstract: In this paper, we explore the effect of charge on the stability of pulsar star SAX J1748.9-2021 in $f(Q)$ gravity, where $Q$ represents non-metricity. For this purpose, we apply the Krori-Barua metric ansatz with anisotropic fluid and use a linear $f(Q)$ model $f(Q)=\zeta Q$, where $\zeta$ is a non-zero constant. We derive exact relativistic solutions of the corresponding field equations. Furthermore, we study its geometric and physical properties through astrophysical observations from the pulsar SAX J1748.9-2021, which is found in X-ray binary systems within globular clusters. We examine features like anisotropic pressure, the mass-radius relationship, redshift, the Zeldovich condition, energy and causality conditions, the adiabatic index, the Tolman-Oppenheimer-Volkoff equation, the equation of state parameter and compactness. Our findings align with the observational data which indicate that the pulsar SAX J1748.9-2021 is viable and stable under this modified theory of gravity.