Physical properties and the maximum compactness bound of a class of compact stars in $f(Q)$ gravity

Abstract: We investigate the physical behaviour of a stellar configuration by developing a compact stellar model within the framework of $f(Q)$ gravity. We study the mass-radius ($M-R$) relationship and obtain the maximum compactness bound of the resultant stellar configuration by assuming the modification to be linear in non-metricity $Q$, i.e. $f(Q) = \alpha\ Q + \beta$. The maximum compactness bound proposed in $f(Q)$ gravity is analogous to the Buchdahl bound in general relativity. We note that the compactness bound increases in $f(Q)$ gravity. In the general relativistic limit ($\alpha=-1$), our approach regains the Buchdahl bound for an incompressible star. Our observation might be relevant in the context of a recent observation with the MeerKAT observatory, which indicates the existence of high mass non-black hole compact objects which cannot be modelled by using the conventional neutron star equation of state (EoS).